ONTARIO

SUPERIOR COURT OF JUSTICE

COURT FILE NO.: CR-19-4584

DATE: 20201013

Decision released orally and in writing

BETWEEN:

HER MAJESTY THE QUEEN

– and –

Michael Todd Hiller

Accused

Craig Houle and Megan Cleland, for the Crown

Evan Weber, for the Accused

HEARD: February 24, 25, 26, 27, 28, 2020; March 2, 3, 5 and 6, 2020

reasons for judgment

POMERANCE j.:

[1] Michael Hiller is charged with manslaughter. The Crown alleges that he caused the death of Joel St. Louis during a fight. The cause of death was a cardiac arrest. The Crown alleges that the accused caused the cardiac arrest by placing the deceased in a “headlock” or “armlock” that compressed the deceased’s neck. The Crown alleges that, while on top of the deceased, the accused wrapped his arm around the deceased’s neck, placing pressure on the neck and causing the heart to stop. For ease of reference, I will refer to the alleged act as a headlock. The accused testified at trial. He admitted to fighting with the deceased but denied ever placing him in a headlock or otherwise compressing his neck. The accused testified that, during the fight, he was acting in self defence.

[2] The central issue in this case is causation. Causation is an essential element that must be proved beyond a reasonable doubt. Here, the question is whether the accused committed the act alleged to have caused death – the headlock resulting in neck compression. There is no direct evidence of a headlock. No one saw this act, and the accused denies it. The Crown theory is exclusively based on the testimony of the forensic pathologist, Dr. Edward Tweedie. Dr. Tweedie inferred, from his observations, that there had been compression of the neck. Dr. Tweedie testified that, in cases of strangulation, there were usually external marks on the neck. Because there were no such marks in this case, he concluded that the pressure to the neck was caused by an arm, rather than hands. On this basis, Dr. Tweedie inferred that a headlock was the act that caused death.

[3] This is an unusual case. In most homicide trials, there is no controversy over the act that caused death. There might be questions about who committed the act, or whether the accused intended the act, or whether the act was justified, but there is little question that the act occurred. This case is different. We know that death was caused by cardiac arrest, but the question is what caused the cardiac arrest. Was it an act of the accused? Was it the act alleged by the Crown? Has the Crown proved that element of the offence beyond a reasonable doubt?

[4] The case for causation is entirely circumstantial. Dr. Tweedie’s opinion is based on an inference that he drew from his observations. Because the Crown’s case pivots on this inference, it must be the subject of a careful and critical evaluation. It is the fine thread that separates a finding of guilt from an acquittal.

[5] Dr. Tweedie is an esteemed forensic pathologist. He has performed thousands of autopsies and has testified in countless cases. While I am respectful of his expertise, it is incumbent upon me to independently assess the basis for his conclusion before I accept and apply that conclusion. My role as a gatekeeper and, in this case, as a fact finder, requires that I not simply trust a witness because he is an expert, even an esteemed expert. It is open to me to question and, if appropriate, reject an expert opinion where I can articulate a basis for doing so.

[6] Here, the expert’s opinion bears the full weight of the criminal standard of proof. I find that it is not sufficiently robust to meet that challenge. Dr. Tweedie’s opinion on the cause of death does not prove, beyond a reasonable doubt, that the accused caused the death of Mr. St. Louis. My conclusion is based on Dr. Tweedie’s own testimony, in which he acknowledged that there are alternate explanations for each of the observations that he described to the court.

[7] I will elaborate on this conclusion in the reasons that follow.

[8] I will begin with a summary of the evidence leading up to and surrounding the altercation. I will then briefly discuss the testimony of Dr. Tweedie. After discussing the general principles governing expert opinion evidence, I will turn to a more fulsome analysis of the testimony of Dr. Tweedie in this case.

EVIDENCE

Background

[9] Mr. Hiller and Ms. Botosan were married in 2003 and have two daughters. By March 2018, their union was not a happy one. Mr. Hiller had been living elsewhere for a time, but in December 2017, he moved back into Ms. Botosan’s house in order to be close to his daughters and help with the bills. It was agreed that, while the two shared a residence, they were separated and could see other people. Ms. Botosan was seeing Mr. St. Louis, who was himself married at the time. Mr. Hiller testified that he was less than pleased about that relationship. According to him, his displeasure with their relationship was because the two appeared to drink a lot when they were together.

The Evening of March 23, 2018

[10] On the night leading up to the incident, Mr. Hiller went to Gatsby’s bar and grill, where he had dinner and some alcoholic beverages. While there, he sent various text messages to Ms. Botosan. Some of the messages spoke about her relationship with Mr. St. Louis. He was there for about three hours and left at about 10:00 p.m. or 10:30 p.m.

[11] On the way home, Mr. Hiller decided to stop at Jake’s Joint, another bar that was close to the home he shared with Ms. Botosan. In his testimony, Mr. Hiller said that he did not know that Ms. Botosan and Mr. St. Louis were at that location. However, he acknowledged in cross-examination that he expected the two to be together on a Friday night, and he knew that they spent a lot of time at this establishment. Indeed, they were in the bar when Mr. Hiller arrived. He insisted in his testimony that he did not stop in for that reason. He parked his van in the back, entered through the back door, and made his way to the main area of the bar.

Inside Jake’s Joint

[12] The Crown tendered videotaped footage of activity in Jake’s Joint that night. There was no audio, but the video depicted various points of interaction between Mr. Hiller, Ms. Botosan and Mr. St. Louis.

[13] Ms. Botosan claimed to have no memory of any events in the bar. She viewed the video, confirmed that she was the person depicted, but could not recall anything that occurred, or anything that was said by the parties at the time. She only remembered the end of the night. She sent a text to Mr. Hiller at 1:53 a.m. on March 24, 2018 telling him, “don’t come home”. She recalled the text and testified that she sent it because Mr. hiller had been abusive toward her while at the bar, calling her a “whore”.

[14] She testified that she received texts from Mr. Hiller while she and Mr. St. Louis were at Jake’s Joint. She also described a telephone call in which Mr. Hiller asked her if she was at home. She told him that she was at Jake’s Joint, and he said that he was going to stop by. Mr. Hiller did not recall this conversation.

[15] Mr. Hiller was critical of Ms. Botosan’s behaviour that night. He testified that he believed her to be acting in a flirtatious or promiscuous fashion, and he told her so. Mr. St. Louis came to Ms. Botosan’s defence and told Mr. Hiller that he should stop criticizing her. There were two occasions when the tension between Mr. Hiller and Mr. St. Louis was sufficiently palpable that Nicholas Jacobs, whose family owned the bar, went over to break the two men up.

[16] Mr. Hiller testified that, when he began criticizing Ms. Botosan’s behaviour in the bar, Mr. St. Louis took issue with this and told him to “shut up about Mary”. At one point, as Mr. Hiller was going to the washroom, Mr. St. Louis stopped him and said, “are you going to get your Queensmen to beat me up tonight?” This was a reference to the individuals Mr. Hiller had been drinking with. According to Mr. Hiller, Ms. Botosan came over to the table while he and Mr. St. Louis were speaking. She was calling him names, and both she and Mr. St. Louis were upset with him. Mr. Hiller tried to defuse the situation by apologizing. He and Mr. St. Louis shook hands.

[17] The Crown theory is that Mr. Hiller sought out Ms. Botosan and Mr. St. Louis, that he initiated the contact with the two of them, and that he was the person provoking conflict that night. The Crown alleges that Mr. Hiller was obsessed with the relationship, perhaps because he still had romantic feelings for Ms. Botosan.

[18] When Ms. Botosan and Mr. St. Louis left the bar, Mr. Hiller was still there. He remained for a brief time and then drove home to the house he shared with Ms. Botosan and his two daughters.

Events at the House: Testimony of the Accused’s Daughter

[19] That night, one of Mr. Hiller’s daughters had a friend sleeping over. His two daughters and the friend were sleeping in his daughter’s bedroom in the basement. Shylynne Hiller, the oldest daughter, testified at the trial. She testified that at around 2:30 a.m. on March 24, 2018, she heard her father shouting and yelling and slamming kitchen cupboards. She went upstairs and tried to calm him down. He was swearing and seemed angry. She took him to her sister’s bedroom and talked him into going to sleep. He told Shylynne that he did not want Joe coming in the house, and that he knew that Joe and Ms. Botosan were outside in the truck. He started to cry at one point, telling Shylynne that he did not want Joe to be her new dad. Shylynne went back downstairs, but it was not long before she heard more shouting. She came upstairs and looked outside to see her father standing outside, beside Mr. St. Louis’s truck. She saw him knocking on the window and yelling. She then saw him come back into the house and go back downstairs. He passed her on the way in, and she did not see anything in his hands.

[20] She went downstairs, only to hear yelling once again. She went upstairs and saw her mother and Joe come into the house. She was in the kitchen and could see the front door from her vantage point. Shylynne testified that her father was yelling at Joe to get out, and her mother was saying that she did not want Joe to leave. Shylynne then saw her father push Joe out the door of the residence. Joe was standing at the door frame, and her father pushed him out of the house with his hands on his chest. The two started wrestling and punching at one another. They were on the concrete just outside the door and then moved onto the sidewalk, still punching at one another. Then, they were on the ground wrestling. Shylynne could not remember who was on top initially, but the two men rolled on the ground, leaving Mr. Hiller on top of Mr. St. Louis. This all happened very quickly.

[21] Shylynne saw her mother run outside and start pulling at Mr. Hiller to get him off of Mr. St. Louis. Shylynne went out to help her. She saw Mr. Hiller on top of Mr. St. Louis but could not see what he was doing. At one point, Mr. Hiller got up and went into the house. Shylynne testified that it was very dark in the front yard. This was confirmed by others, such as the EMS worker who attended on scene.

[22] Shylynne stayed outside with her mother. Mr. St. Louis was face down on his chest, not moving. Shylynne helped her mother roll Mr. St. Louis over. Ms. Botosan said she was going to perform CPR. She began compressing Mr. St. Louis’s chest, alternating with breathing into his mouth.

[23] Shylynne went back downstairs to her bedroom, and Mr. Hiller entered, crying and saying that he “didn’t mean to hurt him”. Mr. Hiller went into the bathroom and Shylynne followed him. He was still crying and said that, while at the bar, “Joe said he was going to mess him up.” Shylynne went back into her bedroom. She saw the police outside and wanted to stay with her sister.

Events at the House: Other Evidence

[24] Mr. Hiller testified that, while in the house, he observed lights and saw Mr. St. Louis’s truck parked outside. Ms. Botosan testified that she and Mr. St. Louis were sitting in the truck having a cigarette. Mr. Hiller went outside and approached the couple in the truck. There are differing accounts of precisely what happened at this stage. Ms. Botosan testified that Mr. Hiller came out with a knife and began to approach the vehicle, but then turned around and went back inside. As noted above, Mr. Hiller’s daughter testified that she saw him go up to the truck and knock on the window. She saw him come back into the house and testified that his hands were empty; there was no knife. Mr. Hiller testified that he could not remember why he went outside, but that he went up to the truck and asked, “what are you doing?”

[25] Whatever happened at the truck, it is agreed by all that Mr. Hiller went back inside the house. According to his daughter, he was very agitated.

[26] It is also common ground that, at one point, Mr. St. Louis walked Ms. Botosan to the front door of the house. Ms. Botosan testified that she asked Mr. St. Louis to do this, because she felt threatened by Mr. Hiller’s earlier behaviour. Ms. Botosan testified that as she and Mr. St. Louis were at the doorway, Mr. Hiller began yelling at Mr. St. Louis to get out of the house. Ms. Botosan responded by saying it was her house. According to her, Mr. Hiller then came down the stairs and shoved her down. She managed to get back up and saw Mr. Hiller coming back into the house. She saw Mr. St. Louis lying on the ground face down. She started to shake him and kept saying his name. He was not conscious and was not moving. Her daughter was beside her. She turned Mr. St. Louis over and began performing “mouth to mouth”. An ambulance arrived, and she stopped. She did not see any change in his condition.

The Altercation

[27] It is not clear just where Mr. St. Louis was standing when he walked Ms. Botosan up to the doorway. Ms. Botosan testified that he was standing just outside of the door, as did Shylynne. Mr. Hiller testified that Mr. St. Louis was actually inside the residence. Mr. Hiller was upstairs in the kitchen area when he saw Mr. St. Louis. He rushed down the stairs towards him. Ms. Botosan testified that she was knocked over by Mr. Hiller in his rush to get at Mr. St. Louis, though this was not confirmed by Shylynne.

[28] When Mr. Hiller got to where Mr. St. Louis was standing, one of the two men initiated aggression. Shylynne testified that Mr. Hiller pushed Mr. St. Louis out the door. Mr. Hiller testified that Mr. St. Louis pulled him out the door. Whatever caused the movement, the force caused the two men to back up against the wall of the house, with Mr. St. Louis striking his head on the brick. The altercation continued, and the two men ended up on the ground.

[29] According to Shylynne and Ms. Botosan, Mr. Hiller was on top of Mr. St. Louis. Mr. Hiller testified that Mr. St. Louis was on top of him. This is questionable. Mr. Hiller agreed that Shylynne and Ms. Botosan kept yelling at him, “get off of him” meaning get off of Mr. St. Louis. If Mr. St. Louis was, indeed, on top of Mr. Hiller, those comments would make no sense. In addition, Mr. Hiller testified that he wriggled free of Mr. St. Louis while Mr. St. Louis was on top of him. Mr. St. Louis was by all accounts a much larger man that Mr. Hiller. It is difficult to imagine how he would have freed himself if he had indeed been pinned down by Mr. St. Louis’s weight.

[30] The fight was brief. Neither Shylynne or Ms. Botosan were able to see precisely what each of the parties was doing. No one observed Mr. Hiller holding Mr. St. Louis in a choke hold, or with his arm around Mr. St. Louis’s neck.

Arrival of the Paramedics

[31] Shawn May was one of the paramedics that responded to the call for assistance that night. He received a call to attend at the Daytona address at around 2:30 a.m. The only information that he and his partners received was that there was an unconscious male, who potentially had been drinking. The paramedics sped to the address with lights and sirens. It was very dark that night, and they were having difficulty seeing house numbers on Daytona drive. They arrived at 2:50 a.m. and saw a female on top of a male. She was waving them down. Mr. May headed toward them while his partner and his student got the necessary equipment.

[32] Mr. May saw the male lying supine on the grass on his back. He was covered in grass and mud. The female was frantically yelling and trying to perform compressions on his stomach, rather than his chest. She was grabbing his head in an effort to provide mouth to mouth ventilations. The male appeared to be “vital signs absent”. He believed there to have been a cardiac arrest. He observed multiple trauma on the male’s arms and legs, and trauma to the forehead and head. He was “purplish blue” and “mottled” from the neck up to the top of his face. The female kept trying to perform mouth to mouth resuscitation. She also appeared intoxicated and was impeding the paramedics’ efforts.

[33] Mr. May took over CPR and conducted a hands-on assessment. The male was not breathing. Initially Mr. May performed chest compressions, but then his partner came over and applied “E-Fib” pads – pads on the chest to see the heart rhythm and defibrillate. The defibrillator had a screen that showed the rhythm of the heart. At that time, there was no heart activity at all.

[34] Mr. May began CPR work on an airway. It was a cold morning, and Ms. Botosan was being obstructive, so they moved the male into the ambulance for further treatment. Once inside the vehicle, Mr. May began working on creating an airway. He inserted a laryngoscope – a lighted handle with a blade that is inserted in the airway to displace tissues, mainly the tongue and epiglottis. He tried to insert the tube but was unsuccessful. The male was a larger man, and it was difficult to displace the tissues in this mouth. He did not want to move the neck too much. Mr. May decided to use a different airway adjunct. He reinserted a basic airway which provided air through a resuscitation bag. This oral pharyngeal airway is curved like a horseshoe. It goes back and pulls the tongue forward. This tube went into the mouth and partially down the male’s throat.

[35] Mr. May began squeezing the bag attached to oxygen in an effort to get the male to start breathing. There was still no heart activity. Mr. May then decided to use a different option – a supraglottic airway, that is placed into the oral pharyngeal cavity – through the mouth into the esophagus and behind the trachea. This new device was successfully placed, and the airway was established.

[36] This process was very difficult as the male was a large man and had a lot of tissue in his neck.

[37] There was still no pulse. Mr. May started using medications, such as epinephrine. It eventually had an effect, causing there to be a pulse and a rhythm in the heart. This took place at 3:15 a.m., approximately 18 minutes after the paramedics’ arrival. Mr. St. Louis was taken to the hospital. While on route, he went into cardiac arrest once again. The use of CPR and epinephrine brought back a pulse.

[38] Mr. St. Louis died in hospital some days later.

Testimony of Dr. Tweedie

[39] Dr. Tweedie testified that the immediate cause of death was hypoxic ischemic encephalopathy, meaning that the brain was damaged due to interruption of blood supply and oxygen delivery. The interruption of blood supply and oxygen was said be caused by a cardiac arrest. Dr. Tweedie concluded that the cardiac arrest was caused by neck compression – the act alleged to have been carried out by the accused.

[40] Dr. Tweedie’s opinion may be summarized as follows:

1. The immediate cause of death was hypoxic ischemic encephalopathy, meaning that the brain was damaged due to interruption of blood supply and oxygen delivery.

2. The interruption of blood supply and oxygen was caused by a cardiac arrest.

3. Dr. Tweedie inferred from his observations that the cardiac arrest was caused by neck compression.

4. Dr. Tweedie inferred that, because there were no marks on the neck, as one would usually observe, the neck compression was caused by an arm lock – the placing of an arm around the neck, rather than the placing of hands on the neck.

[41] In reaching his conclusions, Dr. Tweedie relied on four factors:

1. The occurrence of a cardiac arrest;

2. The fracture of the superior horn of the larynx;

3. The presence of petechial hemorrhages under the eyelids; and

4. The “history” of events, namely, the fact that there was an altercation.

[42] Dr. Tweedie summarized his opinion as follows:

Q. And when you say it was your opinion that that was due to neck compression, how did you arrive at that conclusion?

A. Through a combination of historical information around the circumstances where he was found, by the subsequent course in hospital, and investigations that were done party to exclude other causes, and from my examination where I was able to exclude other causes of cardiac arrest and found no other alternative cause of death structurally. And then also from the positive findings that I've partly outlined thus far that indicate that there was application of force to his neck, and those would include some of the neck injuries I've described thus far, and also - or which I haven't mentioned, is that there was some bruising in the muscles at the back of his neck. And then there's a - another observation I made and that was the presence of conjunctival petechial hemorrhages, so little hemorrhages on the - the lining of the eyelids that indicate that there had been a raised pressure in those blood vessels, and that is a sign of backing up of blood which can result from pressure applied to the neck which prevents blood from returning down to the heart, it backs up in veins ultimately to the small blood vessels lining the eyeballs, and because of that increase in pressure, they will rupture. There are other causes for petechial hemorrhages, but certainly neck compression is the well-recognized cause. Usually the rule would be that those would be present when there has been significant neck compression, potentially life-threatening. So my - ultimately, my conclusion is really reliant on all those factors.

[43] Dr. Tweedie formed the opinion that the accused had placed the deceased in a headlock, on the basis that there were no external injuries to the neck:

A. Yes. I think two things I could comment on, just going back I mentioned that there were no external injuries to the neck, I should say that that is - is fairly unusual when one concludes or when strangulation has occurred. Most instances where there has been strangulation, particularly when there's more of an altercation and someone is conscious and able to fight, there's usually more marks on the neck due to the nature of the struggle. So that could be in the form of abrasions and bruises, and so forth. In this case, there were none. And that, to me, suggests that the likely way in which pressure was applied to his neck would not likely be application of pressure with the use of the hands. When the hands are applied in that way, we refer to as manual strangulation. Fingertips, fingernails, multiple projections, projecting surfaces, applying pressure to the neck usually result in skin injuries. So their absence to me suggests that maybe the application of force was done by a broader surface such as what would occur if someone had a headlock around one's - someone's neck, or an arm lock where you wrap your arm around the head and the neck is in the crook of the elbow, and then there's a more diffuse squeezing with no, you know, projecting surfaces that would necessarily bruise or abrade the skin. And then the other part of the question was further observations, I'm not sure I've mentioned that there was some bruising limited to the muscles at the back of the neck. Again, just reflecting some blunt trauma there which could have been due to excessive squeezing of the neck.

[44] Because Dr. Tweedie’s opinion is central to the outcome in this case, I will reserve further discussion of his testimony to the analysis of the causation issue.

ANALYSIS

The Issue: General Principles

[45] The central issue in this case is whether the accused caused the death of Mr. St. Louis. There is no question that the two were involved in a fight at the time of Mr. St. Louis’s death. There is no doubt that Mr. St. Louis suffered a cardiac arrest, and ultimately died as a result. The question is whether Mr. Hiller caused the cardiac arrest, by compressing the deceased’s neck by placing his arm around the neck and squeezing. The Crown says that it has proved beyond a reasonable doubt: 1) that the accused compressed the deceased’s neck by placing his arm around the neck and squeezing; and 2) that the neck compression triggered the cardiac arrest that resulted in death.

[46] Causation is not a daunting threshold. The Crown must simply prove that the act was a significant contributing cause: see R. v. Smithers, 1977 7 (SCC), [1978] 1 S.C.R. 506; R. v. Nette, 2001 SCC 78. The act in question need not be the only cause, or even the dominant cause, of death. Causation is proved if the act contributed to the outcome in a significant way. Therefore, if I were to find that the accused did place the deceased in a headlock, with his arm around the deceased’s neck, that would suffice to meet the causation threshold. On the testimony of Dr. Tweedie, a compression of the neck would have triggered the stopping of the heart.

[47] There is no evidence beyond the testimony of Dr. Tweedie to support the headlock theory. No one observed this act. Neither Ms. Botosan nor the accused’s daughter saw the accused engage the deceased in a headlock. According to them, the altercation was very brief. The accused’s daughter was in the best position to describe the fight, but she did not see anything resembling a headlock. The accused testified and denied ever engaging in this action. The allegation relied upon by the crown – neck compression by way of headlock - is an entirely inferential hypothesis.

[48] The Crown’s case pivots on two inferences drawn by Dr. Tweedie. The first is the inference that the cardiac arrest was caused by neck compression. The second is the inference that the neck compression was caused by an arm around the neck, given the absence of external neck injury.

[49] I will offer three introductory observations to set the stage for the analysis.

[50] First, the Crown did not rely on any alternate theories of causation, and there was no evidence to support any alternate theories. For example, there was no evidence to indicate that the sheer stress of the fight could have induced a cardiac arrest. I must decide this case on the basis of the evidence presented at trial. The Crown relied exclusively on the headlock theory. The Crown argued that it had proven the headlock beyond a reasonable doubt but invited the court to acquit if it was not satisfied that the accused had caused death in this particular fashion.

[51] Second, because the accused testified, denying that he placed the deceased in a headlock, I must apply the principles in R. v. W. (D.) [D.W.], 1991 93 (SCC), [1991] 1 S.C.R. 742 on this issue:

1. If I accept the accused’s testimony that he did not engage the deceased in a headlock, I must acquit;

2. Even if I do not accept the accused’s testimony, if it leaves me with a reasonable doubt on whether he engaged the deceased in a headlock, I must acquit; and

3. Even if the testimony of the accused does not leave me with a reasonable doubt, I can only convict if, on the evidence as a whole, the Crown has proved that the accused engaged the deceased in a headlock, thereby causing death, beyond a reasonable doubt.

[52] Third, because the allegation of guilt is based on circumstantial evidence, the inference of guilt must be the only reasonable inference arising on the evidence. In R. v. Villaroman, 2016 SCC 33, [2016] 1 S.C.R. 1000, at paras. 37-38, the Supreme Court of Canada explained:

When assessing circumstantial evidence, the trier of fact should consider “other plausible theor[ies]” and “other reasonable possibilities” which are inconsistent with guilt: R. v. Comba, 1938 14 (ON CA), [1938] O.R. 200 (C.A.), at pp. 205 and 211, per Middleton J.A., aff’d, 1938 7 (SCC), [1938] S.C.R. 396; R. v. Baigent, 2013 BCCA 28, 335 B.C.A.C. 11, at para. 20; R. v. Mitchell, [2008] QCA 394 (AustLII), at para. 35. I agree with the appellant that the Crown thus may need to negative these reasonable possibilities, but certainly does not need to “negative every possible conjecture, no matter how irrational or fanciful, which might be consistent with the innocence of the accused”: R. v. Bagshaw, 1971 13 (SCC), [1972] S.C.R. 2, at p. 8. “Other plausible theories” or “other reasonable possibilities” must be based on logic and experience applied to the evidence or the absence of evidence, not on speculation.

Of course, the line between a “plausible theory” and “speculation” is not always easy to draw. But the basic question is whether the circumstantial evidence, viewed logically and in light of human experience, is reasonably capable of supporting an inference other than that the accused is guilty.

[53] In this case, the evidence is reasonably capable of supporting an inference other than the guilt of the accused. The Crown has failed to disprove other exculpatory possibilities. These are not speculative possibilities. They are possibilities that are directly derived from Dr. Tweedie’s testimony.

THE JUDICIAL APPROACH TO EXPERT EVIDENCE

[54] There was a time when trial judges simply deferred to expert witnesses. They were the ones with specialized knowledge, impressive credentials and, sometimes, inaccessible vocabulary. Experts were sometimes seen as virtually infallible, or at least, immune from effective challenge by a non-expert. However, the cloak of infallibility fell away some years ago. In his report on the inquiry into the Pediatric Forensic Pathology in Ontario Commissioner: The Honourable Stephen T. Goudge, Report of the Inquiry into Pediatric Forensic Pathology in Ontario: Executive Summary, Vol 1; (Toronto: Ontario Ministry of the Attorney General, 2008) (the “Goudge Report”). Justice Goudge documented the tragic impact of faulty expert evidence by Dr. Charles Smith, that led to a series of wrongful convictions. The dangers of flawed expert testimony were more recently the subject of study in relation to the use of Motherisk Hair Analysis laboratories: (see The Honourable Susan Lang, Motherisk Hair Analysis Independent Review (Toronto: December 17, 2015); The Honourable Judith C. Beaman, Harmful Impacts: The Reliance on Hair Testing in Child Protection (Report of the Motherisk Commission) (Toronto: February 2018). In the wake of these reports, and related case law, courts have a duty to carefully assess the validity of expert opinion evidence. (see R. v. Bingley, 2017 SCC 12, [2017] 1 S.C.R. 170, at para. 36)

[55] Justice Goudge recognized the heavy burden resting upon trial judges to prevent miscarriages of justice:

Judges also play an important role in protecting the legal system from the effects of flawed scientific evidence. Although this objective will be greatly assisted by the use of rigorous quality assurance processes in preparing expert opinions, by the integrity and candour of expert witnesses, and by vigorous testing of expert evidence by skilled and informed counsel, the judge must bear the heavy burden of being the ultimate gatekeeper in protecting the system from unreliable expert evidence – evidence that can, as our Inquiry showed, contribute to miscarriages of justice.

Executive Summary, Vol 1, at 47

[56] The court is to take an evidence-based approach to scientific evidence, both as gatekeeper and fact-finder. The admissibility of expert evidence must be guided by the rigorous two stage test set out in White Burgess Langille Inman v. Abbott and Haliburton Co., 2015 SCC 23, [2015] 2 S.C.R. 182, recently summarized in R. v. Biddersingh, 2020 ONCA 241, at para. 37:

In determining whether expert evidence is admissible, the trial judge must engage in the two-stage test adopted by the Supreme Court of Canada in White Burgess, Langille, Inman v. Abbott and Haliburton Co., 2015 SCC 23, [2015] 2 S.C.R. 182. At the first stage, the trial judge must determine whether the threshold requirements of admissibility are met: a) the evidence must be logically relevant; b) it must be necessary to assist the trier of fact; c) it must not be subject to any exclusionary rule; d) the expert must be properly qualified, including being willing and able to fulfil their duty to the court; and e) for any opinions based on novel science or science used for a novel purpose, the underlying science must be reliable: R. v. Abbey, 2017 ONCA 640, 140 O.R. (3d) 40, at paras. 47-48; White Burgess, at para. 23. If these requirements are met, the trial judge must advance to the second stage, in which they are required to fulfil a “gatekeeping role”: Abbey, at paras. 48, 53; White Burgess, at paras. 20, 24. As the gatekeeper, the trial judge must determine whether the benefits of the evidence outweigh its potential risks, considering such factors as legal relevance, necessity, reliability, and absence of bias: Abbey, at para. 48; R. v. J.-L.J., 2000 SCC 51, [2000] 2 S.C.R. 600, at para. 28.

[57] Where, as here, admissibility was not challenged, an equally rigorous approach must govern the assessment of the weight to be attached to the expert testimony. This is particularly so where the expert opinion is the centerpiece of the case for the Crown. As it was put in White Burgess:

The trier of fact must be able to use its “informed judgment”, not simply decide on the basis of an “act of faith” in the expert’s opinion: J.-L.J., at para. 56. The risk of “attornment to the opinion of the expertˮ is also exacerbated by the fact that expert evidence is resistant to effective cross-examination by counsel who are not experts in that field: D.D., at para. 54.

[58] Similar comments were offered by the Court of Appeal in Abbey no. 2, at para. 119:

In his article on the Goudge Report, “Taking a ‘Goudge’ out of Bluster and Blarney: An ‘Evidence-Based Approach’ to Expert Testimony” (2009) 13 Can. Crim. L. Rev. 135, Professor David Paciocco, now Paciocco J.A. of this court, aptly commented that courts now take what he called, and what the Goudge Report called, an evidence-based approach to the evaluation of the reliability of expert evidence. He wrote at p. 146: “In effect, the ‘trust me’ approach, once typical in Canadian courts, has been replaced by a ‘persuade me’ standard”. And near the end of his article, at p. 155, in words directly relevant to the reliability of Totten’s opinion evidence, he wrote: “…the essence of an evidence-based approach is that the tribunal be given all of the data it needs to assess the opinion it is being asked to accept. Anything less and a ‘trust me’ approach is used.”

[59] This is not to say that trial judges ought to approach experts with a jaundiced eye. Expert testimony should not trigger automatic suspicion, but nor should it trigger deferential worship. No category of witness is infallible. The testimony of an expert is like the testimony of any witness. The trier may accept all, part or none of the evidence. When the witness is an expert whose opinion leads inexorably to a finding of guilt, the court is not only entitled, but obliged, to understand the reasoning process of the expert and critically assess whether it represents proof beyond a reasonable doubt.

JUDICIAL INTERVENTION IN THIS CASE

The Procedure

[60] Dr. Tweedie testified twice at the trial. He initially testified as the first witness for the Crown, at which time he expressed his opinion as to the cause of death. Several witnesses testified after Dr. Tweedie, including Shawn May, the paramedic that attended to the deceased at the scene of the incident. Mr. May was the last witness for the Crown. He testified about the steps he took to create an airway for the deceased and restart the heart. Dr. Tweedie did not have Mr. May’s report when he conducted the autopsy and wrote the initial report. He did receive it before testifying and said that it did not change his opinion.

[61] At the close of the case, the matter was scheduled for closing submissions. In the interim, as I reviewed the whole of evidence led at trial, I began to have questions about certain aspects of Dr. Tweedie’s testimony. When I reviewed the evidence in this case, I realized that certain relevant questions had not been put to Dr. Tweedie when he first testified. For example, he had not been asked in detail about the resuscitation measures used by Shawn May, the paramedic, who arrived on scene on the night of the incident (though defence counsel had broached the topic in the original cross-examination). I was also aware that some aspects of Dr. Tweedie’s opinion had been the subject of evidence before the Goudge Inquiry. For example, Dr. Michael Pollanen had testified about the danger of relying on petechial hemorrhages as a sign of asphyxia. This raised questions in my mind. I understood Dr. Tweedie to have relied upon the presence of petechiae in concluding that there was neck compression in this case. Other aspects of the Goudge Report and underlying testimony raised questions about Dr. Tweedie’s approach to the causation issue.

[62] When the matter came back before me for submissions, I expressed my concerns to counsel, and it was agreed that Dr. Tweedie would be recalled to address the issues in question. I provided counsel with the material that I had consulted, so that counsel could explore the issues of concern in their questions. This material was not, itself evidence; rather it was material that Dr. Tweedie could be asked to give evidence about when he re-attended at court.

[63] Dr. Tweedie graciously made himself available to return to the courthouse on short notice. On Monday, March 9, 2020 he returned to give evidence. Both Crown and defence examined him – both were given latitude to cross-examine – and he answered their questions. The questions posed by counsel had addressed some, but not all, of my queries. For the purpose of clarification, I asked a few additional questions of Dr. Tweedie.

Legal Basis for Intervention

[64] These circumstances raised a challenging question: what should a trial judge do when she has questions bearing on the validity of an expert opinion, and those questions have not been put to the witness by counsel?

[65] The starting point for the analysis is the requirement of impartiality. The trial judge must not act in a way that gives rise to a reasonable apprehension of bias. The trial judge must be respectful of the role of counsel and the choices that they make in presenting their case, including tactical or strategic choices. The trial judge must take care not to enter the litigation arena. However, the trial judge, an impartial arbiter, is also the guardian of the integrity of the process. Whether acting as a gatekeeper on the admissibility of evidence, or as a fact finder on the ultimate verdict, judges have an obligation to prevent a miscarriage of justice.

[66] There are arguably four options available to a trial judge in this scenario. First, the trial judge could set aside his or her questions and consider the evidence simply as it was presented by counsel. This, however, would ignore the trial judge’s overarching duty to prevent a wrongful conviction. Where there are genuine concerns about the reliability of expert evidence, they cannot be ignored. To do so would be to revert back to the era where judges trusted, without question, the opinions of experts. It would disregard the evidence-based approach dictated by the Goudge Inquiry and the appellate cases that have followed in its wake.

[67] As a second option, the trial judge could act on his or her concerns by rejecting the expert opinion, without giving counsel or the witness an opportunity to address those concerns. This is improper. For one thing, it would have the trial judge applying extraneous information which was not the subject of evidence, or testing, at trial. For another, it would involve the judge applying specialized knowledge which is the usual domain of an expert witness. These were the problems identified by the British Columbia Court of Appeal in R. v. Bornyk, 2015 BCCA 28, 320 C.C.C. (3d) 393, in which the court reversed an acquittal entered by the trial judge who had conducted and applied his own research about the frailties of forensic fingerprint comparisons.

[68] The third option, equally unacceptable, is for the trial judge to act on the outside knowledge without expressly referring to it. This approach would violate the principles of natural justice which require, at a minimum, that the parties be given the opportunity to know and address the factual elements that lead to a verdict in a criminal trial. A judgment must not be based on extraneous information that counsel – and the relevant witness – have had no opportunity to address.

[69] The fourth option is the one that I chose in this case. I notified counsel of the court’s concerns, and I provided counsel with the material that grounded the concerns. It was agreed that Dr. Tweedie would be re-called to testify so that counsel could put relevant questions to him and give him the opportunity to address the court’s concerns. It was only when counsel did not ask certain questions that I took the unorthodox step of asking them myself. I told counsel in advance the questions I would ask, gave them the opportunity to object to any of the court’s questions, and provided them an opportunity to ask any questions arising out of the court’s inquiries.

[70] Judicial intervention in trial evidence is a very delicate matter. I did not take lightly the decision to proceed in this fashion. My hope was to respect the principles of transparency and fairness, while ensuring that I understood the nature and parameters of Dr. Tweedie’s opinion as to cause of death.

[71] I was guided by, among other sources, the very thoughtful article written by Gary Edmond, David Hamerc & Emma Cunliffe, “A little ignorance is a dangerous thing: engaging with exogenous knowledge not adduced by the parties*” (2016) 25:3 Griffith L Rev 383-413. The authors commented on how a trial judge might address concerns about expert opinion evidence:

Our suggestion is merely that the trial judge be encouraged to express concerns or ‘flag’ some issue(s) at an early stage of proceedings in cases where forensic science evidence appears to play a non-trivial role. The kind of intervention we support is, in fact, quite limited in scope and unlikely to threaten judicial independence or impartiality. Although it might be viewed as disrupting more conservative conceptions of the judicial role, modest intervention is justified to the extent that it advances fundamental trial goals – specifically factual rectitude and fairness. Gentle judicial inquiry might encourage counsel to undertake the kinds of research or preparation that are necessary for procedural safeguards to be (more) effective. As we explain, judicial inaction, such that parties do not know about potential problems and relevant literatures (where they are known to judges) seems to be a more serious and apparently pervasive threat to modern criminal proceedings.

The issue is unlikely to arise in such a pointed manner if intervention is early and restrained. Bringing apparently pertinent matters to the attention of counsel early in the process does not compromise judicial impartiality. Rather, it avoids the need for judges to remain passive where they have knowledge, insights or concerns that do not appear to be shared by counsel. Intervention increases the likelihood that relevant materials will be considered and, where appropriate, brought to the attention of the trier of fact. Intervention may prevent the jury (and courts of appeal) from relying on misleading evidence or evidence that is mistaken or exaggerated. An approach to judicial independence that facilitates prosecution but is insensitive to well-documented problems with the forensic science evidence relied upon, presents a greater threat to judicial independence and to the legitimacy of the criminal process than would many types of judicial intervention. It is vital that our judges maintain independence and impartiality. However, an independent and impartial judge may occasionally be obliged to intervene to encourage more appropriate presentation of forensic science evidence. Some suggestion or inquiry of the prosecutor should be sufficient in the majority of cases. However, where forensic science evidence adduced by the prosecutor is inattentive to, or inconsistent with, mainstream scientific advice or fails to disclose well-documented limitations, uncertainties and criticisms, a fair-minded trial judge should act to preserve the integrity of the trial process

[72] While I consulted extraneous material, such as testimony before the Goudge inquiry, I did not rely on any of that material as evidence in this case. It is not evidence. The material was given to counsel so that Dr. Tweedie could comment on it. He did comment on it when he re-attended at court. To be clear, Dr. Tweedie is the only forensic pathologist who testified at this trial, and his is the only expert testimony that I have considered.

[73] I will now turn to the evidence of Dr. Tweedie in this case.

DR. TWEEDIE’S OPINION: AN OVERVIEW

[74] As noted above, Dr. Tweedie testified that the immediate cause of death was hypoxic ischemic encephalopathy, meaning that the brain was damaged due to interruption of blood supply and oxygen delivery. The interruption of blood supply and oxygen was said be caused by a cardiac arrest. Dr. Tweedie concluded that the cardiac arrest was caused by neck compression – the act alleged to have been carried out by the accused.

[75] In reaching his conclusions, Dr. Tweedie relied on four factors:

1. The occurrence of a cardiac arrest;

2. The fracture of the superior horn of the larynx;

3. The presence of some petechial hemorrhages under the eyelids; and

4. The “history” of events, namely, the fact that there was an altercation.

ALTERNATE EXPLANATIONS

Cardiac arrest

[76] Dr. Tweedie testified that each of the factors he relied upon in reaching his opinion could have an alternate explanation or cause.

[77] Cardiac arrest can occur for an apparently unexplained reason that is undetectable at autopsy.

Fracture of the superior horn of the larynx:

[78] Dr. Tweedie acknowledged that the internal neck fracture was of a non-specific nature. While he suggested that it was a rare event, Dr. Tweedie could not rule out the possibility that the neck fracture was caused by resuscitation efforts of EMS on the night of the incident. I will return to this issue shortly.

Petechial hemorrhages

[79] On the first occasion that he testified, Dr. Tweedie said that, “the petechiae in the eyes, to me, are indicative of prolonged neck compression of sufficient duration to cause the blood pressure in veins to increase to the point where those vessels are ruptured”. He also testified that:

There are other causes for petechial hemorrhages, but certainly neck compression is the well-recognized cause. Usually the rule would be that those would be present when there has been significant neck compression, potentially life-threatening. [Emphasis added.]

[80] When he testified on the second occasion, Dr. Tweedie agreed that petechiae in the eyes can result from any number of other events. These include: sustained heavy pressure to the chest, prolonged positioning of the body in a head down position after death, prolonged forceful coughing or straining, violent or severe throwing up, vigorous or strained activity, or other exertions on the part of the individual. Dr. Tweedie acknowledged that petechiae can last at least a few days, and it is not possible to determine when they occurred. He could not rule out the possibility that the deceased had experienced the petechial hemorrhages before the altercation. Dr. Tweedie did testify that while post mortem lividity can cause petechiae, he did not believe that the deceased had been lying in place long enough for such lividity to occur.

[81] While testifying on the second occasion, Dr. Tweedie agreed with the statement in the Goudge Report that “petechial hemorrhages … are in fact non-specific findings”. He agreed with the proposition that petechial hemorrhages “are in no way limited to asphyxia, they are meaningless without more evidence and cannot be diagnostic of asphyxia”. While he agreed with the statements in the Goudge Report, they did not change his opinion that neck compression was the cause of the petechiae in this case.

THE COMBINED EFFECT

[82] Dr. Tweedie’s opinion was based on the combined effect of all three observations – cardiac arrest, internal neck fracture, and petechial hemorrhages – together with his awareness that there had been an altercation. As he explained:

Q. And although you have a number of factors here that resulted in your opinion that neck compressions that ultimately, or that initially brought on the onset of cardiac arrest, I know that’s your opinion.

A. Correct.

Q. But I’m suggesting to you that there are, it’s possible that in this particular case it was not neck compression it was potentially something else.

A. The findings that I observed are all findings that are not necessarily fatal in and of themselves. A fracture of a superior horn of larynx, isn’t a fatal injury. It doesn’t kill you. Petechiae in the eyes don’t kill you.

But those are markers of neck compression and in this case, evidence for that and we have a history that indicates that he suffered a cardiac arrest in and around the events that resulted in, those findings in the neck which I believe were due to neck compressions.

Therefore, my conclusion is that the cardiac arrest was the result of that. But absolutely I would agree that none of my findings in and of themselves are irrefutable evidence that they killed Mr. St. Louis. And yes, there are instances where hearts stop, and we don’t understand why in the end.

But in this instance, I have a reason based on my findings to explain why his heart stopped in this case. If that answers the question.

A. And there are alternate explanations for all of my findings in addition to the process that I’m propining is the process that occurred. I willing to admit that. I’m just combining everything with the history and forming my opinion on that basis.

THE COURT: when you say “history”, may I just ask what you are referring to?

A. The — just that simply there was a altercation and that he was resuscitated shortly thereafter.

THE COURT: Thank you I’m just going to take a moment.

THE COURT: Again, just for purpose of clarification, Dr. Tweedie, you say there are alternate explanations for all of your findings. So that — How does that figure into the conclusion that you’ve reached? If there are alternate explanations....

A. I weighed the likelihood of those occurring, consider how, what are the common features of the different findings that could be explained with one mechanism as opposed to having to invoke several different ones. For example, the neck fracture conceded could have been due to a direct blow to the neck that caused it. As opposed to this sustained pressure, but to me the presence of the petechiae indicates that or supports that that wasn’t the case. That there was more sustained pressure, one that would also allow for the petechiae to develop. Because a blow wouldn’t cause sufficient rise in the blood pressure for a sufficient period of time in order to cause petechiae. So again, I’m combining those findings and they are complimentary to one another in the sense that they point to a common cause or a common mechanism.

THE COURT: If one of those findings was attributable to something else would that effect your ultimate opinion?

A. Sure, if it could be established that for example, and I don’t know how you would be able to but if for example it was possible to prove that the neck fracture was due to a blow then I wouldn’t necessarily conclude that the petechiae in the eyes were due to sustained pressure around the neck, for example. If it was —- well, that would be an instance.

THE COURT: All right.

A. So, yes. That does have an effect.

A. Right. So, my conclusion not only is based on the findings at autopsy of the post-mortem findings but as I explained earlier, I was provided with some information about an altercation that Mr. St. Louis had with another male and I certainly considered that in formulating my conclusion. And the other important fact was that there was no other apparent structural cause of death. Meaning, I didn’t find evidence of natural disease or drug toxicity or anything else to explain his death. But that was put together with the positive findings that I had at the autopsy. One of which was the conjunctival hemorrhages. But that was really something that I used to support another finding, which was the fracture of his larynx, the superior horn of his thyroid cartilage that was the result of trauma to the neck and the petechiae in combination with that fracture and also some bruising in the neck, to me is collaborating evidence or findings that can be combined to indicate that the pressure to the neck that caused the fracture of the cartilage was of a sustained nature such that it caused the venous return from the head to be impaired and result in those conjunctiva. So, the conjunctiva — To put another way support the mechanism of injury to the neck being that of sustained compression causing that fracture.

ASSESSMENT OF THE REASONING PROCESS

[83] The following paragraphs will outline why the testimony of Dr. Tweedie does not prove causation beyond a reasonable doubt.

Alternate Explanations

[84] First, if each of the observations relied upon by Dr. Tweedie could be explained by a theory other than neck compression, it is not clear to me how combining the observations proves neck compression beyond a reasonable doubt. It would seem equally possible that there was an unexplained cardiac arrest, that the internal neck injury was caused by resuscitation efforts; and that the petechial hemorrhages were caused by some type of ante mortem exertions, including exertions preceding the altercation. The Crown has failed to disprove these exculpatory hypotheses beyond a reasonable doubt.

Contradictory Evidence

[85] At least one observation had the potential to rebut the theory of neck compression, namely, the absence of external neck injuries. Dr. Tweedie testified that it is unusual in cases of strangulation to find no external marks on the neck. Yet, Dr. Tweedie did not use this observation to test his theory of neck compression. Rather, he modified his theory to account for this contradictory observation. He concluded that, because there were no external marks on the neck, the compression must have been caused by a headlock, rather than hands on the neck. The difficulty with this line of reasoning is that it seems to adapt the evidence to suit a pre-existing theory, rather than adapting the theory to reflect the evidence[^1]. As he put it: “there were no external injuries to the neck. I should say that that is – is fairly unusual when one concludes or when strangulation has occurred” [emphasis added]. This statement suggests that the conclusion preceded the observation, rather than the other way around.

Circularity

[86] In other instances, the reasoning is marked by circularity. For example, when he testified on the first occasion, Dr. Tweedie said that: “because I was able to exclude other causes of cardiac arrest, the cardiac arrest was caused by neck compression”. He later testified that, because he found there to be neck compression, the heart had not stopped for an unexplained reason. A was the reason for B, and B was the reason for A.

[87] A similar approach was taken to the neck fracture and the presence of petechiae. Dr. Tweedie found that the fracture of the superior horn was “non-specific in terms of cause. It indicated that there had been an application of pressure forcing the larynx, probably, up against the spine which is located behind the larynx and that caused the tip to break”. The type of force could, according to Dr. Tweedie, be variable. Dr. Tweedie concluded that the neck fracture was “the result of external compression of the neck” because the deceased had petechiae in his eyes. He testified that: “the neck injuries themselves could have other potential causes other than a sustained squeezing action to the neck, but the presence of the eye hemorrhages really, to me, indicates a more sustained pressure application”.

[88] Later, he testified that, while petechiae can be caused by many different things, the internal neck fracture indicated that the fracture was the product of neck compression. The neck injury told him that the petechia were from neck compression, and the petechiae told him that the neck injury was from neck compression.

[89] This, then, leads to the use made by Dr. Tweedie of the altercation itself, what he described as the “history” of the matter.

[90] When asked why he believed the neck fracture to be the product of neck compression, Dr. Tweedie responded:

Because there was an alleged altercation, and because these fractures are commonly seen when pressure is applied to the neck from outside during a struggle and someone is being strangled.”

[91] On other occasions, he testified:

I was provided with some information about an altercation that Mr. St. Louis had with another male and I certainly considered that in formulating my conclusion.

But those are markers of neck compression and in this case, evidence for that and we have a history that indicates that he suffered a cardiac arrest in and around the events that resulted in, those findings in the neck which I believe were due to neck compressions.

[92] Dr. Tweedie did not specify just how the altercation figured into his reasoning process, but he clearly considered this as a factor, as illustrated in this passage:

Q. … were you able to come to any conclusion in terms of when [the internal neck injury] was sustained?

A. No. My presumption is that it was sustained during the incident.

Q. And why is that?

A. Because I wasn’t provided with any other information regarding any events that would account for that injury, other than likely altercation with another individual at the time of – of the incident. As I said, there are different possible ways that one can fracture a superior horn. I was putting it in context with the rest of my findings and the history.

It is entirely proper for a forensic pathologist to consider information about the incident under investigation when arriving at an opinion. However, there are limitations on the use to be made of such circumstantial evidence in arriving at an opinion. As noted in the Goudge Report:

Policy and Recommendation, Vol 3, at 351

Effect of Resuscitation Efforts

[93] I will now turn to the evidence of the internal neck fracture, and the possibility that it was caused by something other than neck compression. This is an important part of the case. If the neck fracture is excised from the causal equation, one is left with nothing more than an unexplained heart attack and the presence of petechial hemorrhages. The case – including the testimony of Dr. Tweedie – does not rule out the possibility that the fracture of the left superior horn of the thyroid was caused by the efforts of EMS personnel to revive and resuscitate the deceased on the night of the incident.

[94] Dr. Tweedie was the first witness at trial; Shawn May was the last. The testimony of Shawn May established that various efforts had been made to resuscitate the deceased at the scene on the night of the incident. When Mr. May arrived, he observed Mary Botosan attempting to perform CPR on Mr. St. Louis, pushing his abdomen and manipulating his neck area. Mr. May himself described the various tubes and devices that he placed in Mr. St. Louis’s neck in an effort to start his breathing and his cardiac rhythm. These were relatively aggressive resuscitation techniques. They went beyond a simple intubation carried out in the relative calm of a hospital setting. Mr. May was trying to revive Mr. St. Louis through any means possible, and he inserted various tubes into Mr. St. Louis’s neck. This was a challenging endeavor as Mr. St. Louis had a fleshy neck which made it difficult to insert with any degree of precision.

[95] Dr. Tweedie was not asked in detail about EMS efforts when he first testified. The Crown did ask Dr. Tweedie whether the internal fracture could have been caused by intubation. Dr. Tweedie knew that the deceased had been intubated at the hospital. He was asked whether intubation could have caused the fracture and he testified that it was very unlikely, though he could not “100 percent” rule it out. His exchange with Crown counsel during his initial testimony included the following:

Q. Dr. Tweedie, the one thing I wanted to clarify with you is when you were making reference earlier in your evidence to intubation as possibly being a cause of bruising. As it relates to that fracture of the superior horn and the efforts for intubation, could that in any way affect the injury that you observed?

A. The question is could the superior horn fracture be a result of intubation?

Q. Yes.

A. I would say very unlikely. I can't say 100 percent that it wasn't. I don't believe I've ever seen a fractured superior horn that was a result of - of intubation. Normally, intubation doesn't require excessive pressure to the neck from the outside. So, there would have to be some unusual circumstances here that I wouldn't be able to readily explain. In the literature, there are some rare case reports, or reports, of hyoid bones and larynxes being damaged during intubation, but it's a - at best, it would be a very rare occurrence.

Q. Okay. And you had indicated to us earlier that you've conducted something in the range upwards of 2500 autopsies in the course of your career?

A. Mm hm.

Q. In the course of those autopsies, have you encountered other decedents who have had intubation as...

A. Yeah.

Q. ...as a result....

A. When I've encountered broken larynxes, there's always been a traumatic explanation independent of resuscitation related injury.

Q. And you're indicating in none of those 2500 examinations that you've conducted have you seen an injury to the superior horn as a result of intubation that we see the injury here?

A. Correct. Correct.

[96] When Dr. Tweedie performed his post-mortem examination and formulated his opinion on the cause of death, he was not aware of the EMS evidence. He had apparently been given a copy of the EMS notes sometime after he wrote his report, and he had seen those notes before he testified. He testified that the EMS notes did not change his opinion.

[97] When Dr. Tweedie re-attended court, he was asked more specifically about the EMS efforts to resuscitate the deceased:

Q. You - you, obviously, can't offer us any comment on what took place when you weren't there. But hypothetical speaking, if Mr. St. Louis was not breathing and EMS personnel were responding and attempted to enter - or attempted to insert an orotracheal intubation tube, if it can be called that, could that device, or that instrument, actually come into contact with any of the portions of the neck that you've been referring to?

A. Yes. It could come in contact, certainly, with the base of the tongue, where there were some bruises. It can also, by definition, is meant to come into contact with the lining of the throat and the larynx as it goes down through that passageway, and in contacting the edges or the mucosa, as we call it, it can damage that and cause some hemorrhage. And I do describe that as the - as being present at the time of death. That might just be a result of that tube - any normal tube staying in there for that prolonged period or it could have caused damage at the time it was inserted, I don't know.

Q. Is the hyoid area, or bone...

A. It's not....

Q. ...exposed?

A. It's not directly in - in the line, but in the - in the line of the intubation attempt. So, it shouldn't be directly traumatized. As I said, though, there are rare case reports where broken hyoids have been attributed to difficult intubations. Exactly how that occurs during the process and why, I don't know.

Q. Yes. You indicated that in the number of autopsies you've seen, you've never - I think the question was put to you, have you ever seen a fracture from intubation?

A. Right.

Q. In a....

A. My experience is - is, no. Much of - we rely not only on personal experience, in fact it's improper to rely only on personal experience to form opinions about things. There's a body of literature that people report, based on their experiences, studies, retrospective studies, looking at a number of cases, in order to provide an evidence-based literature base which we utilize regularly in order to answer questions for which we may not have personal experience or for which we want stronger medical evidence to support our conclusions.

Q. Okay. And would - when you - when you mentioned that the - the proposition that you would need unusual circumstances, would a non-medical person attempting to perform CPR on an individual, whatever that means, would that fall under unusual circumstances in your opinion?

A. Normal CPR wouldn't traumatize the neck and cause this injury. I don't know if someone doesn't know what they’re doing and they squeeze the neck, then that could result in this sort of an injury.

[98] Given Mr. May’s testimony, I felt it necessary to ask Dr. Tweedie some additional questions about the actions of EMS officers:

THE COURT: I think I just have only one question then I’ll let counsel ask any questions arising from my inquiries. In your earlier testimony you were asked whether intubation could cause the trauma to the neck that you observed in this case.

A. Yes.

THE COURT: And you testified that would be very rare.

A. Yes. I can’t completely exclude it but if it was the cause it would have been a very rare event, a very rare occurrence. Intubation is a very frequently performed procedure and if that was a frequent or even occasional occurrence that would be well recognized.

It’s as I said, in the literature, there are some cases that make note of neck injuries related to intubation so I can’t one hundred per cent exclude that that didn’t occur here.

THE COURT: May I ask, what sorts of circumstances those are?

A. I don’t know what would have been the particular reason for those having occurred in the instances in which they did.

THE COURT: Hypothetically if in this case, or hypothetically in a case, there were three attempts at intubation by EMS workers arriving at a scene. Including, and forgive my pronunciation of these, a laryngoscope and then an oropharyngeal Airway...

A. Yes.

THE COURT: ...both of which were unsuccessful leading to a supraglottic airway being inserted into the neck. Would that have any impact on your view?

A. I don’t know if the repeated attempts would increase the likelihood of an injury occurring. I don’t know.

THE COURT: All right. So that — All right. Did you take into account the possibility of those procedures when you arrived at your opinion in this case?

A. I am aware that there are potential artifacts of resuscitation. So, I had considered those in this instance.

THE COURT: Were you aware of those three attempts at intubation that I just....

A. No. I guess I wasn’t because I wasn’t provided with the specifics of the resuscitation until just before my prior appearance. So, I was at that point, yes. But my — I had already written my report.

THE COURT: Yes.

A. Would it change my opinion?

THE COURT: Yes.

A. No.

[99] It is apparent from these passages that Dr. Tweedie could not rule out the possibility that resuscitation efforts had caused the internal neck fracture. He acknowledged that “there are rare case reports where broken hyoids have been attributed to difficult intubations”, but he could not explain how or why that occurs. He testified that it was “rare” for that to happen, and that he had never seen it occur in the thousands of autopsies that he performed. Dr. Tweedie referred to “literature” but did not identify any specific articles to support his conclusion. He acknowledged that “some cases that make note of neck injuries related to intubation so I can’t one hundred per cent exclude that that didn’t occur here”. He did not identify the cases he was referring to and did not know “the particular reason for those having occurred in the instances in which they did”.

[100] Despite these cases, the “literature”, and Mr. May’s testimony, Dr. Tweedie maintained his opinion that the internal facture was caused by neck compression:

A. Again, I wouldn’t, I think it would be a very rare occurrence. Much more likely that the fracture was the result of external compression of the neck.

THE COURT: And why do you say that, given the nature of the intubation? I’m simply trying to understand why that is.

A. Because he had petechiae in his eyes. Because there was an alleged altercation and because these fractures are commonly seen when pressure is applied to the neck from outside during a struggle and someone is being strangled.

THE COURT: All right.

A. And there are alternate explanations for all of my findings in addition to the process that I’m propining is the process that occurred. I willing to admit that. I’m just combining everything with the history and forming my opinion on that basis.

THE COURT: When you say “history”, may I just ask what you are referring to?

A. The — just that simply there was a altercation and that he was resuscitated shortly thereafter.

THE COURT: Thank you I’m just going to take a moment.

[101] Ultimately, Dr. Tweedie remained “confident” in his conclusion that there had been neck compression:

A. There is some element of opinion here. Sometimes a cause of death is irrefutable. Gunshot wound to the head, for example. In this case, this is an opinion I’m making using the totality of all those elements that I’ve talked about before. I’m confident in my conclusion. I don’t know how I can quantify a degree of certainty that’s of any help to the court.

[102] Dr. Tweedie had two reasons for maintaining his theory of neck compression. First, he testified that it was “much more likely” that the fracture was caused by neck compression. Even if that be so, this case is not about likelihoods; it is about whether the Crown has proved guilt beyond a reasonable doubt. Even if it is more likely than not that the accused caused death, this does not suffice to make out causation on the criminal standard of proof.

[103] The second apparent reason for Dr. Tweedie’s opinion is his perception that it is “rare” for such injury to result from intubation or resuscitation efforts. The Crown took pains to lead evidence of the number of autopsies performed by Dr. Tweedie, and the fact that he had never seen such an caused in such a fashion. This type of anecdotal statement is not of great assistance to the courts. Whether or not Dr. Tweedie had seen this type of injury before, he acknowledged that there is literature confirming that it can happen.

[104] In R. v. Vassel, 2018 ONCA 721, 365 C.C.C. (3d) 45, at para. 94, Watt J.A. stated:

A final point concerns anecdotal evidence, which sometimes enters the record of trial proceedings during the testimony of an expert. Anecdotal evidence is testimony that does not speak to the facts of the case but reasons from the witness’s prior experience to the probability of a particular result or occurrence in the case at hand. Anecdotal evidence is not legally relevant. Nor is it necessary. It lacks probative value. It is inherently prejudicial and tends to shift the onus of proof to an accused: Sekhon…

[105] To a similar effect is R. v. Awer, 2016 ABCA 128, 37 Alta. L.R. (6th) 62, in which a DNA scientist testified that he had never seen a dry transfer of so much DNA. In his dissent in the Alberta Court of Appeal, Berger J.A. held that this statement should not have been relied upon by the trial judge. His reasons include the following, at paras. 122 and 130:

Numerous cases demonstrate the potential for anecdotes and unsystematic observations of experts to be overvalued. The prejudicial effect that follows is especially pronounced in the scientific world where observations only gain statistical significance if obtained through controlled, peer-reviewed empirical studies of a known and sufficiently large sample size. Given the general mystique and complexity of certain sciences such as DNA analysis, the risk of the trier of fact simply accepting the utility of the scientist’s “field” observations is heightened. Thus, the prejudice to the accused is even greater where anecdotes come from the mouth of a scientific expert. A trial judge should vigilantly question a scientist’s experiential observations to ensure compliance with the scientific method. That did not happen in this case.

The trial judge should not have so readily accepted the utility of Mr. Denison’s statement that he had never seen such an amount of DNA transferred from dry contacts. There is no way of assessing the probative value of his conclusory statement, except to blindly trust his expertise and experience. After all, Dr. Libby testified that the forensics community has not recognized or accepted any threshold concentration of DNA above which signifies a wet origin. The significance of observations made in the course of forensic DNA quantitation analyses rests entirely on scientific validity. The trial judge erred by relying heavily on Mr. Denison’s testimony; in preferring his testimony to Dr. Libby’s, and in drawing her ultimate inference of guilt largely on that basis.

[106] On further appeal to the Supreme Court of Canada, 2017 SCC 2, [2017] 1 S.C.R. 83, at para.2, Moldaver J. declined to offer a definitive ruling on the DNA evidence, though he did advert to the need for further evidence about the foundation for the anecdotal assertion:

Because we have concluded that a new trial must be ordered, we need not finally decide whether the impugned evidence of the Crown’s DNA expert as to the source of the complainant’s DNA, found on the appellant’s penis, was or was not admissible. If an attempt is made to tender that evidence at the new trial, a voir dire may be required to determine whether it is sufficiently reliable to warrant its reception. It could conceivably amount to circumstantial evidence, derived from the expert’s experience, from which an inference as to the origin of the complainant’s DNA could reasonably be drawn. Alternatively, it might prove to be purely speculative, with little or no scientific foundation. Whatever the case, I note that it differs qualitatively from the impugned evidence in R. v. Sekhon, 2014 SCC 15, [2014] 1 S.C.R. 272, where false logic, devoid of any probative force, was used to infer the state of mind of persons transporting large quantities of illicit drugs across the U.S.-Canada border

[107] In this case, Dr. Tweedie testified that he had never seen an internal neck fracture caused by resuscitation efforts. This does not speak to whether it occurred in this case. Rare events can and do occur. I note, as an aside, that Dr. Tweedie would only have seen this phenomenon in the past if he was looking for it. In his testimony, he fairly acknowledged that he was not particularly familiar with the literature documenting this event. He could not advise the court of the circumstances in which it might occur. If this was not something that he had actively considered, he might not be able to accurately advise on whether or not it had occurred. In any event, Dr. Tweedie himself acknowledged that it is improper to rely on personal experience to form opinions; that evidence-based literature is the appropriate source for such conclusions.

Peer Review

[108] The Crown relies on the fact that Dr. Tweedie’s report was subject to peer review. Another forensic pathologist reviewed the case report documenting Dr. Tweedie’s findings, and approved it. I do not have any evidence as to what was placed before the reviewing expert. For example, was that individual made aware of the resuscitative efforts of Shawn May? Dr. Tweedie did not receive the EMS notes until sometime after he had completed his report. Dr. Tweedie testified that those notes did not change his opinion. Against that backdrop, it may well be that the notes did not make their way into the peer review. In any event, I do not see the existence of peer review as a guarantee of reliability. It is, to be sure, an important safeguard against error. It does not, however, prevent the trier of fact from reviewing the reasoning process of the primary expert. My concerns are not based on a raw review of the expert’s report. They arise directly as a function of Dr. Tweedie’s own testimony about how he processed and analyzed the data before him. The fact that the case was reviewed and approved by a professional peer must be considered, but it does not detract from the logical implications of Dr. Tweedie’s testimony, outlined above.

Findings relating to the Testimony of Dr. Tweedie

[109] The Crown has failed to prove causation beyond a reasonable doubt.

[110] This would be a very different case if there had been independent evidence of the act alleged to have caused death. If any witnesses had seen the accused engage in a headlock maneuver, or if the accused had admitted to the act, then the testimony of Dr. Tweedie could well establish a causal link between that act and the death of Mr. St. Louis. The difficulty is that there is no evidence that the act occurred, beyond Dr. Tweedie’s inferential hypothesis. There is very little evidence about what occurred during the fight, save for the observation that both men were aggressors.

[111] I refer again to the test in Villaroman. The Crown must establish that the only reasonable inference to draw in this case is that the accused engaged the deceased in a headlock, resulting in neck compression that caused death. On the basis of Dr. Tweedie’s testimony, that is one inference; but it is not the only reasonable inference.

[112] There are gaps in the narrative of what occurred during the fight. The encounter was brief; it was dark; and witnesses did not see very much. The court must avoid the human temptation to fill the gaps with unsupported or speculative inferences in order to arrive at a cohesive story: see Villaroman, at para. 29. The courts must also advert to the possibility of bias, including confirmation bias, when an expert witness testifies. Such bias is often unconscious and can occur despite an expert’s experience, competence and renown. It would obviously be wrong for an expert to begin with the assumption that the accused caused the death of Mr. St. Louis. So too must the court avoid this type of reasoning. The fact that there was a fight does not, without more, prove that the accused’s actions during the fight caused the death.

[113] Third, it is important to understand that forensic pathologists are not trained to formulate hypotheses on the criminal standard of proof. “Proof beyond a reasonable doubt is a legal standard applicable to the totality of evidence, and it has no correlation with science or medicine” (Goudge Executive Summary, p.73). From a purely diagnostic or medical perspective, neck compression may well present as a possibility in this case. However, where, as here, the expert opinion is the only evidence of causation, it cannot meet the threshold of proof beyond a reasonable doubt.

[114] The basic question, set out in Villaroman, is whether the circumstantial evidence, viewed logically and in light of human experience, is reasonably capable of supporting an inference other than that the accused is guilty. Given the denial by the accused that he engaged in a headlock; the fact that no other witnesses saw a headlock; and Dr. Tweedie’s acknowledgement that his observations could have alternate explanations, there are reasonable bases on which to infer that this was a tragic event, resulting in death, for which the accused is not criminally liable.

CONCLUSION

[115] For the reasons given, I cannot be satisfied beyond a reasonable doubt that the accused caused the death of Mr. Louis. My decision in this case should not be taken to diminish the tragedy of Mr. St. Louis’s death or the loss experienced by those who loved him. Terrible things can happen even when no one is criminally at fault.

[116] The Crown advised that it was not seeking a verdict of guilt on the lesser included offence of assault, given that the accused and victim were engaged in a consensual fight. Therefore, I need not consider whether the accused was acting in self defence. The case hinges exclusively on the issue of causation. The failure of the Crown to prove that the accused

caused the death of Mr. St. Louis necessitates that I enter an acquittal on the count of manslaughter before the court.

Original signed by Justice Renee Pomerance

Renee M. Pomerance

Justice

Released: Delivered orally and in writing – October 13, 2020

COURT FILE NO.: CR-19-4584

DATE: 20201013

ONTARIO

SUPERIOR COURT OF JUSTICE

HER MAJESTY THE QUEEN

– and –

Michael Todd Hiller

REASONS FOR JUDGMENT

Pomerance J.

Released: Delivered orally and in writing – October 13, 2020

[1] THE COURT: I have a question, a clarification question, and perhaps I'll ask it now so that if there are any questions arising from it, they can be asked afterwards. My question is this; Dr. Tweedie, you - if I'm - on a few occasions referred to presumed resistance and you also referred to the headlock position, and I was wondering whether you were actually offering an opinion about the likely positions of the parties or is that just one of any number of possibilities that could be consistent with the evidence?

A. It's just one of many possibilities. My speculation that a headlock-type hold may have been used in this instance is based on the relative lack of external injuries to the neck, in the presence of the internal injuries, and the congestive signs in the face which suggest pressure to the neck.

THE COURT: All right.

A. The way to apply pressure to the neck without leaving skin wounds and not using a - you know, without leaving skin wounds would be most consistent with a - an armlock if the pressure if the result, or occurring, during a fight. Grasping of the neck with the hands in order to choke someone or manually strangle them, would almost certainly leave more skin injuries in this instance. In addition, his neck was quite broad, it would be very difficult to get one's hands around the circumference of his neck, in fact. That would be my opinion. And there would no skin wounds to suggest that a ligature was used here, like a rope, because that would almost certainly leave a - a distinct mark, unless it was a very broad ligature like a scarf, or something, that could apply pressure over a broad area, much like a - an arm, and an elbow, and an upper arm could.

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