Court File and Parties

Ontario Court of Justice Old City Hall – Toronto

Between: Her Majesty the Queen

And: Varun Sriskanda

Counsel:

• D. Morlog, for the Crown/Applicant
• L. Adler, for the Offender/Respondent

Heard: October 25, 2016

Reasons for Ruling

Re Admissibility of Expert Evidence

Justice Melvyn Green

A. INTRODUCTION

[1] Varun Sriskanda pled guilty to two counts of trafficking in a "Schedule II" substance, namely "hashish oil (shatter)". Neither "hashish oil" nor "shatter" is defined by statute or specifically listed in Schedule II to the Controlled Drugs and Substances Act (the CDSA). Unauthorized "trafficking" in any substances included in any of the Schedules to the CDSA is prohibited. Those listed in Schedule II are restricted to cannabis (including "marihuana"), its preparations and derivatives (including "cannabis resin", commonly referred to as hashish), and synthetic cannabis and chemical analogues of cannabis. Counsel have proceeded throughout on the assumption that "shatter", like hashish, is a concentrated or condensed form of cannabis.

[2] Both cannabis sales to which Sriskanda pled guilty were to an undercover member of the Toronto Police Service (TPS). He also acknowledges a third sale to the same undercover officer. All three involved hand-to-hand transactions of very small amounts (single grams) of shatter. Following his arrest and transport to a police station, a search was executed at an apartment, "Unit 206", from which the offender had been surveilled coming and going. Three men were found inside the apartment, along with evidence of drug trafficking paraphernalia and some equipment alleged to be associated with the production of shatter.

[3] To be clear, neither Sriskanda nor any of the men found within the apartment were ever charged with production of shatter. Nonetheless, the Crown, by way of what has mutated into a week-long "Gardiner hearing" stretched across some fifteen months, seeks to establish as aggravating factors on sentencing that Sriskanda was involved in the inherently dangerous production of shatter and, further, that this concentrate is significantly more harmful to its users than the dried marihuana leaf that makes up the vast bulk of cannabis sold and consumed in Canada.

[4] In pursuit of this goal, Crown counsel proposes to call "expert evidence" respecting, inter alia, the dangers flowing from the manufacture and use of shatter. The defence opposes the admission of this evidence. Following an admissibility voir dire, I have determined that the tendered expert evidence ought not to be received. My reasons follow.

B. EVIDENCE

(a) Introduction

[5] As set out in its Notice of Intention to Produce Expert Testimony, the Crown, through its proposed "expert witness", Sgt. Tyrone Hilton, seeks to lead evidence pertaining to the following "area of knowledge":

The composition of Shatter, its use and methods of consumption; pricing, packaging, and paraphernalia related to the use and sale of Shatter; modus operandi of Shatter traffickers; methods of production and chain of distribution; and the dangers associated with [its] use, sale and manufacturing.

While casting a broad net, the themes of primary importance to the Crown, as earlier noted, are those included in the final recital: "the dangers associated with [the drug's] use … and manufacturing" – dangers, it is suggested, that jeopardize the health of consumers of shatter and the safety of those involved in or physically proximate to its production.

[6] By way of ultimate disposition, the defence advises it seeks a discharge rather than a sentence that necessarily imports a conviction. The Crown takes a very different view. Both to rebut the defence position and for the express purpose of elevating the current tariff in cases of sentencing for shatter trafficking, the Crown intends to demonstrate that the hazards associated with the production and use of shatter are so substantial that a discharge would be leniently disproportionate to the gravity of the offence. Accordingly, it is the purported "dangers" that flow from the manufacture of shatter and personal consumption of the drug sold by Sriskanda that ground the potential relevance of the proposed expert evidence. To the degree that they bear on use- and production-related harms, the "use and methods of consumption" of shatter and its "methods of production" are also of potential relevance. However, in the absence of a constructive shatter trafficking charge (and there is none), I see no probative value to any other facet of the tendered "area of knowledge", nor does Crown counsel suggest otherwise.

[7] The evidentiary basis for the admission of the Crown's expert evidence thus rests on two pillars. The first is composed of the predicate facts arising from the circumstances of the offences and some of the items located during the search of the apartment linked to Sriskanda. These facts afford the case-specific foundation for the formation of Sgt. Hilton's expert opinion. The second is the testimonial and documentary evidence led on this admissibility voir dire as to Sgt. Hilton's qualifications and the sources on which he relies in formulating his opinion. I turn, then, to the first of these considerations.

(b) The Predicate Facts

[8] As noted, the three pieces of shatter sold by Sriskanda each weighed approximately one gram. The cost of the shatter on each occasion was $70. That the items sold by Sriskanda contained cannabis is reflected in his plea. There is no evidence, however, as to the THC content – that is, the quantitative concentration of the psychoactive ingredient in cannabis – in any of the three purchased pieces of shatter. Crown counsel fairly advises that no quantitative analyses were conducted.

[9] During the search of Unit 206, the police seized a further gram of shatter and a little over a half-kilogram of dry leaf marihuana. Again, there was no forensic analysis of the THC content of either the shatter or the marihuana. The police also located, on a kitchen counter, a butane torch, a vacuum sealer, a marihuana grinder, digital scales and a bong (a cannabis smoking device). They also found a money counter, a vacuum pump and a box of butane canisters in the closet of an adjoining bedroom. No evidence was led of the immediate or on-going production of any drug, including shatter. While items notoriously consistent with drug trafficking were located and, if only arguably, some related to shatter production, no evidence was tendered on this voir dire of any residue, laboratory apparatus, production notes or schedules, instructions, manuals or any other physical indicia of a controlled drug ever having been manufactured in Unit 206.

(c) Sgt. Hilton's Qualifications and Sources

[10] Sgt. Tyrone Hilton was an 18-year veteran of the TPS. He assumed the rank of sergeant with a Primary Response Unit in October 2015. Previously, and but for one year, he had since 2006 worked in the area of drug enforcement, including four years as a supervisor of the Clandestine Drug Unit (CDU) of the Toronto Drug Squad. Hilton had participated in some 150 investigations during these years, primarily focused on methamphetamine and MDMA labs and marihuana "grow ops".

[11] None of the CDU investigations conducted on Hilton's lengthy watch involved the production of shatter. Hilton was not aware of any active shatter production labs ever having been investigated by the TPS. On a single occasion, in the spring of 2014, he attended what had been described to him as a shatter lab. The related investigation was not under his supervision; the lab was not active at the time the police attended; and there was no evidence of any explosion or other production-related accident or adversity. Indeed, to the best of Hilton's knowledge the police had yet to confirm a shatter production-related accident in the Toronto area. Hilton had participated in a handful of shatter trafficking (not manufacturing) investigations, all at the one-gram level. He had also spoken to "a couple" of traffickers. He had never interviewed a user or producer of shatter.

[12] Hilton attended Ontario laboratory investigator courses on a near-annual basis since 2007. None had touched on shatter until his most recent recertification program, in 2015. Shatter production was not the focus of the 2015 program and the materials filed with Hilton's "Opinion" do not include any reference to the contents of the shatter-related portion of the course. Hilton has also lectured on clandestine drug laboratories, but shatter was never part of his syllabus.

[13] Hilton does not have a degree in biology, chemistry, pharmacology or any of the physical or medical sciences. He candidly conceded having no training respecting the effects of shatter. His knowledge of shatter extraction processes was primarily gleaned from conversations he had with other officers, all unnamed. His independent research consisted of Googling "shatter" on the Internet. He had not tried to contact the authors of the articles or postings he located or any other possible experts. He had not updated the information he had collected or otherwise sought to educate himself since preparing his written opinion some ten months before being called on this voir dire. Hilton had never been qualified as a shatter expert. Indeed, he had never been qualified or otherwise testified as an "expert" in any proceeding.

[14] The concluding paragraph in Hilton's written "Opinion" begins with the words, "The production and distribution of shatter needs to be taken seriously". The "associated risks", he continues, "are real and pose a serious risk to society". Drawing on his Internet probes, in the next and final sentence Hilton allows that, "the associated risks with consumption of shatter are still not concrete in the medical field".

C. ANALYSIS

(a) The Law Governing the Admissibility of Expert Evidence

[15] "Opinion evidence" is generally subject to exclusion. Properly qualified "expert" evidence is one settled exception to this general rule. ("Lay", or non-expert, opinion evidence is another.) Expert opinion evidence may, for analytical purposes, be subdivided into several subsets, the two most immediately important of which are expert scientific evidence (reliant on application of the scientific method and principles) and expert non-scientific evidence (which primarily rests on the knowledge of the witness gained through his experience and training). (See R. v. Abbey, 2009 ONCA 624, 97 O.R. (3d) 330 (Ont. C.A.), esp. at paras. 108-115.) Both relate to what the Supreme Court in White Burgess Langille Inman v. Abbott and Haliburton Co., 2015 SCC 23, [2015] 2 S.C.R. 182 (hereafter, "White Burgess") characterizes, at para. 15, as "matters requiring specialized knowledge". While counsel agree that the governing test for admissibility is that set out in the seminal case of R. v. Mohan, [1994] 2 S.C.R. 9, the non-"scientific" nature of the tendered evidence modifies the approach to the threshold considerations.

[16] As expert opinion evidence is "presumptively inadmissible" and as its receipt is resisted in these proceedings, it is the tendering party – here, the Crown – that "must establish its admissibility on the balance of probabilities": R. v. Abbey, supra, at para. 71. A two-stage process of inquiry is contemplated: Abbey, at para. 76; affd. in White Burgess, at para. 22. Satisfaction of the near-canonical four Mohan criteria composes the first, or threshold, stage:

• Relevance;
• Necessity;
• The absence of any exclusionary rule; and
• A properly qualified expert.

(See, also, Justice Richard Schneider's helpful restatement of these prerequisites in "Expert Evidence: Judges as Gatekeepers", in The Lawyer's Guide to the Forensic Sciences, Ed. C. Pakosh, Irwin Law, 2016, 23, at 29). While juries may appear more susceptible to the risks associated with unfiltered expert evidence, the rule and its rationales apply to both jury and judge-alone trials: R. v. J.J., 2000 SCC 51, [2000] 2 S.C.R. 600, at para. 56.

[17] Counsel have chiefly directed their dueling submissions to the question of Sgt. Hilton's qualifications, the fourth criterion in the Mohan ordering. I also have some concerns about the first and second, relevance and necessity. As said by the Supreme Court in R. v. D.D., 2000 SCC 43, [2000] 2 S.C.R. 275, at para. 46, "Mere relevance or 'helpfulness' is not enough". No exclusionary rule (the third criterion) is engaged by this application other than the opinion evidence rule itself.

[18] The second step in the admissibility inquiry arises only if the threshold criteria are met. It imposes a gatekeeping function on a court by way of a cost-benefit analysis or a weighing of the evidence's probative value against its prejudicial effect or, as sometimes put, a measuring of "reliability versus effect" which, as said in Mohan, at para. 18, "has special significance in assessing the admissibility of expert evidence". (See also White Burgess, at para. 24.) Unlike the bright-line rules engaged by the first step, the second involves an exercise of judicial discretion. As explained by now-Justice David Paciocco and Professor Lee Stuesser, the single Mohan test is operable in a broad variety of circumstances "because the gate-keeping component" – that is, the second step – "makes its application highly contextual": The Law of Evidence, 6th Ed., Irwin Law, 2011, at 192.

[19] With respect to the conduct of both stages of the prescribed analysis, the Court in White Burgess observed, at para. 20, that the "unmistakable overall trend of the jurisprudence … has been to tighten the admissibility requirements and to enhance the judge's gatekeeping role." The Court's earlier decision in R. v. J.J., supra, at para. 28, illustrates this stringent approach:

The admissibility of the expert evidence should be scrutinized at the time it is proffered, and not allowed too easy an entry on the basis that all of the frailties could go at the end of the day to weight rather than admissibility.

And as said in R. v. Trochym, 2007 SCC 6, [2007] 1 S.C.R. 239, at para. 27:

Reliability is an essential component of admissibility. Whereas the degree of reliability required by courts may vary depending on the circumstances, evidence that is not sufficiently reliable is likely to undermine the fundamental fairness of the criminal process.

[20] The concern to safeguard the record from bias informs both steps of the admissibility inquiry. In Mouvement laïque québécois v. Saguenay (City), 2015 SCC 16, [2015] 2 S.C.R. 3, at para. 106, the Supreme Court made clear that, "an expert's opinion must be independent, impartial and objective". Considerations bearing on the "properly qualified expert" criterion and, in particular, the risk of bias, are the primary focus of the Court's reasons in its White Burgess decision. As summarized in the following excerpt from the Court's own headnote:

Expert witnesses have a duty to the court to give fair, objective and non-partisan opinion evidence. They must be aware of this duty and able and willing to carry it out. The expert's opinion must be impartial in the sense that it reflects an objective assessment of the questions at hand. It must be independent in the sense that it is the product of the expert's independent judgment, uninfluenced by who has retained him or her or the outcome of the litigation. It must be unbiased in the sense that it does not unfairly favour one party's position over another. …

Concerns related to the expert's duty to the court and his or her willingness and capacity to comply with it are best addressed initially in the "qualified expert" element of the Mohan framework. A proposed expert witness who is unable or unwilling to fulfill his or her duty to the court is not properly qualified to perform the role of an expert. If the expert witness does not meet this threshold admissibility requirement, his or her evidence should not be admitted. Once this threshold is met, however, remaining concerns about an expert witness's compliance with his or her duty should be considered as part of the overall cost-benefit analysis which the judge conducts to carry out his or her gatekeeping role.

Of note, at para. 27 of the judgement proper the Court expressly adopted the dictum of Creswell J. in National Justice Compania Naviera S.A. v. Prudential Assurance Co., [1993] 2 Lloyd's Rep. 68 (Q.B.), at p. 81; endorsed on appeal: [1995] 1 Lloyd's Rep. 455 (C.A.)](https://www.bailii.org/ew/cases/EWCA/Civ/1995/1995_1_Lloyd_Rep_455.html), at p. 496: "An expert witness … should never assume the role of an advocate".

[21] As regards the fundamental concern for reliability, the Supreme Court has effectively adopted the American threshold test for the assessment of expert "scientific" evidence, – that is, the test set out in the famous American case of Daubert v. Merrell Dow, 509 US 579 (1993): see R. v. J.J., supra, at para. 33 and R. v. Trochym, supra, at para. 24. However, the Daubert factors used to assess the reliability of opinion evidence resulting from application of the scientific method (random testing, peer review, reproducibility and potential error rates, for example) are not necessary preconditions to the admissibility of "non-scientific" expert evidence – such as a psychiatrist's opinion as to a defendant's sanity or fitness and, of course, as characterizes the species of opinion evidence here tendered by the Crown. Put otherwise, not all tendered expertise must meet the rigours of the scientific method to warrant admission. Reliability remains essential to receipt of any expert opinion evidence, but a more flexible approach that focuses on the proposed expert's professional qualifications, personal knowledge and in-field experience may, depending on the issue, satisfy a court's threshold concerns in this realm.

[22] In non-scientific circumstances, as here clearly obtain, reliability assessment is approached differently than in cases subject to application of orthodox scientific methodology. In Abbey, supra, at para. 119, Doherty J.A. developed an inventory of appropriate alternative questions:

• To what extent is the field in which the opinion is offered a recognized discipline, profession or area of specialized training?
• To what extent is the work within that field subject to quality assurance measures and appropriate independent review by others in the field?
• What are the particular expert's qualifications within that discipline, profession or area of specialized training?
• To the extent that the opinion rests on data accumulated through various means such as interviews, is the data accurately recorded, stored and available?
• To what extent are the reasoning processes underlying the opinion and the methods used to gather the relevant information clearly explained by the witness and susceptible to critical examination by a [trier of fact]?
• To what extent has the expert arrived at his or her opinion using methodologies accepted by those working in the particular field in which the opinion is advanced?
• To what extent do the accepted methodologies promote and enhance the reliability of the information gathered and relied on by the expert?
• To what extent has the witness, in advancing the opinion, honoured the boundaries and limits of the discipline from which his or her expertise arises?
• To what extent is the proffered opinion based on data and other information gathered independently of the specific case or, more broadly, the litigation process?

To the degree they are directly pertinent, I pay heed to these questions in assessing the admissibility of the purported expert evidence tendered at these proceedings. I am also mindful of the caution urged by Schneider J., supra, at 36: "Expert evidence should be used sparingly, surgically, and only when necessary".

(b) Applying the Law

(i) Introduction

[23] The proposed expert evidence, as earlier noted, is said to be relevant to two aggravating factors on sentencing. The first flows from the hazards purportedly associated with consumption of shatter. The second attaches to hazards alleged to be related to the production of the substance. I address each in turn.

(ii) Risks Associated with Consumption of Shatter

[24] Under this head, the Crown theory of enhanced liability is premised on the elevated THC content of the drug, shatter, sold by Sriskanda. The Crown's expert is prepared to testify that the very high concentration of THC in shatter jeopardizes the health of its users. The patent difficulty with applying this line of reasoning to the case before me is that there is no evidence whatsoever as to the quantum of THC in the drugs purchased from the offender.

[25] Put otherwise, the challenge to the Crown's application under this head of concern is fundamentally one of relevance. Even if it were soundly established that there are health-related harms associated with consuming a highly concentrated form of THC, there is simply no evidence that the psychoactive content of the drugs sold by Sriskanda is in any way greater than the range of THC typically found in street-level cannabis products.

[26] The admission of expert evidence is not an academic exercise. The concern is not the language – "shatter", in the instant case – used to market a drug. The concern, rather, is whether the drugs sold actually contain a measurably higher dosage of the psychoactive ingredient THC. If not, the putative harm, on the evidence before me, is purely speculative. Put differently, an expert's answer to a "hypothetical" question is of no value without an evidentiary nexus to the very subject of the court's inquiry. In an action in tort, for example, no matter how renowned the actuary, his or her assessment of the financial liability of a broken hip is irrelevant absent evidence that the plaintiff has suffered such fracture.

[27] Mohan, like every subsequent authority, forbids admission of expert evidence that is not logically relevant – that is, probative of a material issue. Accordingly, and on this basis alone, Sgt. Hilton's opinion respecting the potentially harmful consequences of consuming shatter fails to meet the threshold requirements for admissibility.

[28] Although unnecessary to my determination, even were there evidence that the products sold by Sriskanda contained inordinately high levels of THC concentration, I would still decline to permit adduction of Hilton's proposed expert evidence on this point. Hilton's written opinion, as filed on this hearing, reflects the highly unsettled nature of the science respecting the harmful effects of consuming shatter and of its modes of administration. Further, by his own admission and on application of any professional standards, Hilton's academic training, credentials, directly related police experience and research methodology simply do not render him, as put by Mohan, a "properly qualified expert" respecting the health-related consequences of consuming shatter.

[29] Even if Hilton's opinion cleared the threshold requirements, the attenuated benefit – that is, the probative worth – of his evidence is simply overborne by the cost, the risk of prejudice, associated with its admission.

(iii) Risks Associated with Production of Shatter

[30] Here the Crown's central proposition, put at its highest, is that the use of volatile elements and pressurized environments in the production of shatter creates fire- and explosion-related risks that are dangerous to those involved in the drug's manufacture and those in close proximity. This hypothesis, as expressed in Sgt. Hilton's written opinion, is heavy on theory and light on any claim to science, professional experience or expertise.

[31] I am prepared to accept (at least for the purpose of the enquiry at hand) that the study of clandestine drug labs is, in the language of Abbey, supra, at para. 119, a "recognized discipline, profession or area of specialized training". I am, however, mindful of the need to constrain, as put in Abbey, the "nature and scope" of the tendered expert evidence to both the points at issue and the compass of the proposed witness's expertise so to avoid the risk of overreaching that has engendered a number of notorious miscarriages of justice: see Abbey, esp. at paras. 62-64, and R. v. Sekhon, 2014 SCC 15, [2014] 1 S.C.R. 272, at para. 46.

[32] Simply put, the evidence led at this hearing does not persuade me that Hilton's general expertise in this field of professional endeavour helpfully extends to contested matters bearing on the production of shatter. Said otherwise, and in answer to the third question in Doherty J.A.'s inventory, Hilton's personal qualifications do not encompass the very issue of direct concern: the hazards purportedly associated with the manufacture of shatter. Hilton has never participated in the investigation of shatter, has conducted no related research of any rigour, and has only very modest exposure to the subject through continuing education. By way of rough analogy: a general ophthalmologist is not likely qualified to express an expert opinion on issues that fall squarely within a narrow subspecialty like ocular immunology and in which the generalist has no specialized training, research history, experience or craft.

[33] I appreciate that not all of the further threshold admissibility questions posed by Doherty J.A. in Abbey apply to every instance of non-scientific expert assessment. Nonetheless, responses afforded by the evidence to those that are relevant are of no help to the applicant. If there are "quality assurance measures" in place or "independent reviews by others in the field" of shatter investigations, I have not been educated about them. There is no indication that data Hilton claims to have gleaned from his fellow, unnamed, officers are "recorded, stored and available" – let alone "accurate". While randomly Googling "shatter" on the Internet may inspire investigative leads, I am hard-pressed to find that this approach amounts to a discipline-approved methodology on which to rest the admissibility of an expert opinion. This is particularly so where, as in the instant matter, Hilton's limited sources are entirely anecdotal. Further, it is unclear how much of Hilton's "data and other information [was] gathered independently of the specific case" – although it appears that Hilton himself collected none of it prior to his retainer.

[34] In short, and as Hilton himself volunteered under oath, he was recruited by the Crown to advance the expert opinion essential to the prosecution's objectives on sentencing. He knew almost nothing about the production of shatter. He spoke to some officers who may have known more, although their names remain a mystery and the documentation of their knowledge, if any, remains undisclosed and unidentified. He "researched" shatter on the Internet, sharing those "hits" that supported the Crown's thesis. He conducted no independent research or experiments. He never attended a facility engaged in the production of shatter or one that was the site of an industrial accident. He interviewed no one engaged in the drug's manufacture. He contacted no authorities on or researchers into the drug's production or any ancillary hazards. He did not track the developments, if any, in the discipline in the ten months between his own Internet inquiries and his testimony in this court.

[35] As regard any risks associated with the production of shatter, I cannot find Hilton to be either an "expert" or one who is "properly qualified". In saying this, I do not mean to foreclose the possibility that there is a recognizable sub-discipline and, somewhere, a duly qualified expert. I mean only that Hilton does not satisfy this Mohan criterion.

[36] Nor, I add, is his proposed evidence, as framed, "necessary" to my fair treatment of this matter. I am prepared to assume that there are at least theoretical risks associated with the production of shatter. What I do not know is whether there is any reliable data respecting their incidence, frequency or magnitude. What is clear, however, is that Sgt. Hilton, by virtue of his own limited training and experience and his reliance on online probings cannot confidently assist in this regard. Accordingly, I find Hilton's evidence respecting the purported dangers of shatter production inadmissible.

[37] While unnecessary for the disposition of this facet of the application, I feel obliged to note that, as gatekeeper, I would be strongly inclined to reject the Crown's application even if Hilton somehow crested the initial Mohan hurdles to receipt of his opinion. This results from my assessment, at the discretionary balancing stage, of the limited probative value of Hilton's evidence, particularly given the patent reliability concerns that attach. As put in Abbey, at para. 87:

When one looks to potential probative value, one must consider the reliability of the evidence. Reliability concerns reach not only the subject matter of the evidence, but also the methodology used by the proposed expert in arriving at his or her opinion, the expert's expertise and the extent to which the expert is shown to be impartial and objective.

I have earlier canvassed my reservations respecting Hilton's methodology and the limits of his claim to expertise. I turn, then and finally, to the matter of impartiality.

[38] Although some scholars have begun to question the practice (see, by way of example, A. Lvovsky, "The Judicial Presumption of Police Expertise" (2017), 130 Harv. L. Rev. 1, esp. at 17ff.), police officers are not barred by their relationship with the Crown from proffering their expertise at the behest of the prosecution. (For one recent example, see the pronouncement of the Alberta Court of Appeal in R. v. Soni, 2016 ABCA 231, at para. 18: "there is no rule that expert witnesses cannot be investigators, and investigators cannot be experts".) As a result, the critical question, as with most tendered experts, is not the witness's professional relationship with the party calling him or her but, rather, the witness's capacity or resolve "to provide the court with fair, objective and non-partisan evidence": White Burgess, para. 49. As noted, these considerations may impact the threshold stage of the inquiry. However, "[a]nything less", the judgement in White Burgess continues, "than clear unwillingness or inability to do so should not lead to exclusion, but be taken into account in the overall weighing of costs and benefits of receiving the evidence" – that is, at the discretionary second stage.

[39] I do not find in Hilton's testimonial posture such "clear unwillingness or inability" as to preclude receipt of his expert opinion on this basis alone at the threshold phase of the inquiry. I am less sanguine, however, upon exercise of my gatekeeping function. White Burgess, at para. 49, unambiguously directs that an expert is not to "assume the role of an advocate for a party". Hilton's gratuitous choice of language in the final paragraph of his written opinion, as quoted earlier, speaks to his partisan advocacy. Rather than merely cataloguing, explaining or interpreting the research or information bearing on his subject and then endeavouring to identify and assess the production-related jeopardy, Hilton's words convey his allegiance to the Crown's more grandiose mission of establishing that shatter is a dangerous drug that "needs to be taken seriously" as it "pose[s] a serious risk to society". Hilton may or may not be right, but it is hardly his role as an impartial expert witness to effectively admonish sentencing courts for failing to join his crusade.

[40] The evidence advanced in aid of Hilton's claims does not satisfy the Mohan criteria nor does it meet baseline reliability concerns. Further, the routine risks of prejudice attending the admission of his opinion is only exacerbated by his partisanship.

D. CONCLUSION

[41] For these reasons the Crown's application to admit expert evidence pertaining to risks allegedly associated with the production and use of "shatter" is declined.

Released on November 22, 2016

Justice Melvyn Green