Court File and Parties

Court File No.: CR-23-00000038-00
Date: 2025-03-07
Ontario Superior Court of Justice

Between:
His Majesty the King – and – Aysar Younes

Applicant Counsel: R. Craig Bottomley and Alison Shields
Crown Counsel: Michael Lunski and Monica Rodrigues

Heard: January 27 and 28, 2025

Ruling #3 – Admissibility of Expert Evidence of Cara Shepard

Muszynski J.

Overview

[1] Aysar Younes is charged with two counts of impaired driving/over 80 causing death and two counts of dangerous driving causing death with respect to a motor vehicle collision that occurred on October 3, 2021 in Trenton.

[2] This trial was originally scheduled to proceed with a jury. On December 23, 2024, Mr. Younes re-elected to proceed to trial with a judge alone. The trial commenced on January 20, 2025 and concluded on January 28, 2025 in Belleville.

[3] In advance of trial, counsel advised the court that a ruling would be required with respect to the admissibility of portions of the anticipated evidence of Cara Shepard—a forensic toxicologist with the Centre of Forensic Sciences (“CFS”). Counsel agreed that the admissibility voir dire would proceed on a blended basis at trial.

[4] At the request of counsel, I provided a bottom-line oral ruling with respect to the admissibility of Ms. Shepard’s evidence with reasons to follow. These are my reasons.

Background

[5] As part of the Crown’s case, a paramedic that treated Mr. Younes following the collision testified that, on the way to the hospital, Mr. Younes reported using cocaine. The paramedic’s evidence was that Mr. Younes seemed confused and ultimately was unsure as to whether he had used cocaine. An emergency department physician testified that Mr. Younes reported drinking alcohol until 4:30 a.m. and using cocaine. In relation to the collision, the emergency department physician recorded the following: “Notes that while driving motor vehicle he was very tired + struggling to stay awake.” On cross-examination, the physician agreed that the notion about 4:30 a.m. related to the alcohol use and not cocaine and that there was no record made about when Mr. Younes used cocaine.

[6] The Crown sought to qualify Ms. Shepard to give opinion evidence on “the analysis of biological samples and the detection, absorption, distribution and elimination of alcohol, drugs and/or poisons in the human body, including alcohol and cocaine as well as the pharmacological and toxicological effects of such substances on the human body and on the ability to operate a vehicle.”

[7] Mr. Younes did not challenge Ms. Shepard’s qualifications. He did not challenge the admissibility of Ms. Shepard’s testimony with respect to blood alcohol concentration, including her opinion on impairment insofar as it relates to alcohol. Rather, the issue relates to Ms. Shepard’s evidence about cocaine use.

[8] Ms. Shepard testified that she conducted a drug screen on a blood sample drawn from Mr. Younes at 2:00 p.m. on October 3, 2021.[1] Ms. Shepard’s evidence is that the blood tested positive for Benzoylecgonine, Levamisole, Phenacetin and Lidocaine. According to Ms. Shepard, Benzoylecgonine is a metabolite of cocaine—which is a substance that remains in the body after the body processes cocaine. Levamisole, Phenacetin and Lidocaine are common adulterants found in cocaine. There was no cocaine identified in the blood. None of the substances that were identified are impairing. I will refer to these substances as “cocaine by-products.”

[9] Ms. Shepard testified that the presence of cocaine by-products enables her to form the opinion that Mr. Younes used cocaine in the days leading up to October 3, 2021. However, she was unable to give an opinion as to:

a) when the cocaine use occurred within that timeframe;
b) the quantity of the cocaine that was consumed; and
c) to what extent the cocaine use would have impaired Mr. Younes’ ability to drive leading up to the collision.

[10] Ms. Shepard gave evidence that following heavy or binge use of cocaine, users can experience a “crash phase” after the stimulating effects of cocaine wear off where they experience extreme fatigue. She was unable to give an opinion as to whether Mr. Younes was experiencing a crash phase associated with heavy or binge cocaine use at the time of the collision.

The Positions of the Parties

[11] The Crown’s application materials, and submissions on the voir dire, identified the probative value of Ms. Shepard’s evidence as supporting the theory that Mr. Younes was impaired by cocaine, or suffering from a crash phase associated with cocaine use, at the time of the collision. The Crown submits that Mr. Younes’ reports to the paramedic and the emergency department physician that he had used cocaine provide a foundation for Ms. Shepard’s opinion. Particularly since the trial is now proceeding without a jury, the Crown submits that the prejudicial effect of Ms. Shepard’s opinion is minimized.

[12] Mr. Younes takes the position that Ms. Shepard’s evidence relating to impairment by cocaine use, or an associated crash phase, is entirely speculative and, accordingly, lacks any probative value. While the prejudicial effect is less significant in a judge alone trial, given the lack of any probative value Ms. Shepard’s evidence about cocaine use should not be admitted.

Issues

[13] Is Ms. Shepard’s evidence with respect to cocaine admissible?

Law and Analysis

[14] Opinion evidence is presumptively inadmissible. An exception, however, is when the opinion is adduced by a properly qualified expert.

[15] The Supreme Court of Canada’s decision in White Burgess Langille Inman v. Abbott and Haliburton Co., 2015 SCC 23, paras. 22-25 establishes a two-step process for admitting expert evidence.[2]

[16] At the first step, known as the threshold step, the four Mohan factors must be established, namely, that the evidence is relevant, necessary, not in violation of any exclusionary rule and that the expert is qualified.[3] At the second step, known as the gatekeeping step, the judge must balance the potential risks and benefits of admitting the evidence in order to decide whether the potential benefits justify the risks.[4]

[17] There is agreement that the proposed evidence is relevant, does not violate any other exclusionary rule and that Ms. Shepard is appropriately qualified. The two main areas of contention involve whether Ms. Shepard’s evidence regarding cocaine is necessary and, if so, whether the potential benefit of the evidence justifies any prejudicial effect.

[18] With respect to necessity, the Crown must establish that the proposed evidence is more than helpful, but the test is not overly stringent. In considering whether the proposed evidence is necessary, the focus is on whether the information is “outside the experience and knowledge” of the trier of fact.[5] Ms. Shepard provides a qualified, relevant opinion in her area of expertise that is beyond the experience and knowledge of the court. I find that Ms. Shepard’s opinion regarding cocaine use meets this threshold step for admissibility.

[19] The second “gatekeeper” step in determining the admissibility of expert evidence requires a balancing of the probative value and prejudicial effects of the testimony. It is at this stage of the inquiry that the Crown’s application to admit Ms. Shepard’s evidence regarding cocaine use falls short.

[20] The Supreme Court of Canada has repeatedly endorsed the sentiment that when discussing probative value, the degree of relevance to the facts in issue and the strengths of the inferences that can be drawn from the evidence must be considered.[6]

[21] I found Ms. Shepard to be a credible witness. She readily conceded the limitations of her evidence regarding cocaine use. For instance, Ms. Shepard cannot provide insight as to whether Mr. Younes was impaired by virtue of cocaine use or experiencing a crash phase at the time of the collision. The most that she can say about cocaine is that Mr. Younes used it, to some extent, in the days leading up to the collision. The Crown’s stated use for Ms. Shepard’s evidence regarding cocaine, was to support the inference that Mr. Younes was impaired by cocaine or experiencing a crash phase associated with cocaine, at the time of the collision. As Ms. Shepard’s evidence is that she cannot opine on either of these two things, I find that her evidence lacks probative value.

[22] While I agree with the Crown that the prejudice to Mr. Younes is significantly reduced now that the trial is proceeding with a judge alone and given his utterances about cocaine use to the paramedic and the emergency department physician, I do accept that there is some minimal prejudicial effect associated with Ms. Shepard’s evidence—which confirms that Mr. Younes had been using illegal drugs. The prejudicial effect of evidence that incidentally exposes the general bad character of the accused must be a factor that is weighed at the gatekeeping stage.[7]

[23] The Crown urged the court to admit Ms. Shepard’s evidence but give it appropriate weight. I considered the weight that I would afford Ms. Shepard’s evidence. I find that Ms. Shepard’s evidence does not assist the court in reaching a conclusion about the collision being caused by impairment or crash phase due to cocaine use. Accordingly, I gave a bottom-line ruling that Ms. Shepard’s evidence related to cocaine use was inadmissible.

Additional Purpose for Adducing Evidence – Request to Revisit Ruling

[24] The continuity or chain of custody of blood samples taken at the hospital was an issue at trial. Mr. Younes took the position that the Crown failed to prove that the blood tested at the hospital, and later by Ms. Shepard at CFS, belonged to Mr. Younes.

[25] In closing arguments, the Crown referred to the drug screen analysis conducted by Ms. Shepard to support the Crown’s position that the tested blood belonged to Mr. Younes. Specifically, the Crown argued that it defies coincidence that the tested blood could have belonged to anyone else given the positive test results for both cocaine by-products and alcohol, considering Mr. Younes reported to the emergency department physician that he had consumed both cocaine and alcohol.

[26] The Crown was confronted about whether it was appropriate to refer to the evidence of Ms. Shepard’s drug screening results given my bottom-line ruling that Ms. Shepard’s evidence related to cocaine lacked probative value and was therefore inadmissible. The Crown took the position that the drug screening results were admissible to support continuity of the blood sample, despite my earlier ruling.

[27] Mr. Younes was given an opportunity to consider the new purpose for which the Crown sought to adduce Ms. Shepard’s evidence. Ultimately, Mr. Younes conceded that Ms. Shepard’s evidence confirming the drug screen results was admissible to support the Crown’s position on continuity but argued that the weight to be afforded to this evidence should be minimal.

[28] I agree with the parties. Evidence can be inadmissible for one purpose and admissible for another.[8] I find that Ms. Shepard’s evidence about the presence of cocaine by-products in the blood sample is admissible for the purpose of establishing continuity. The weight to be afforded to this evidence will be addressed in the trial decision.

Muszynski J.
Released: March 7, 2025

Endnotes

[1] In the trial proper, Mr. Younes challenges the continuity of the blood samples. For the purpose of this ruling only, I have assumed the blood tested by CFS was drawn from Mr. Younes on the date and time specified on the barcoded label on the blood vial.

[2] White Burgess Langille Inman v. Abbott and Haliburton Co., 2015 SCC 23, paras. 22-25.

[3] White Burgess Langille Inman, at para. 23. See also R. v. Mohan, [1994] 2 S.C.R. 9, para. 20.

[4] White Burgess Langille Inman, at para. 24.

[5] R. v. Abbey, [1982] 2 S.C.R. 24, p. 42.

[6] R. v. Handy, 2002 SCC 56, para. 26, citing R. v. Robertson, [1987] 1 S.C.R. 918, p. 943; R. v. Schneider, 2022 SCC 34, para. 60.

[7] R. v. Bush, 2024 ONCA 469, para. 27; R. v. G. (S.G.), [1997] 2 S.C.R. 716, para. 65.

[8] R. v. Burns, [1994] 1 S.C.R. 656, p. 668; R. v. Samuels, 2013 ONCA 551, para. 42; and R. v. Largie, 2010 ONCA 548, para. 84.