Pathology: The Law

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1.0 The Law

1.1 The Coroners Act

In accordance with section 1(1) of the Coroners Act, a forensic pathologist must be certified in forensic pathology by the Royal College of Physicians and Surgeons of Canada or receive equivalent certification in another jurisdiction to be able to provide death investigation services in Ontario [1]. Also, the forensic pathologist must be registered in the Ontario Forensic Pathology Service’s (OFPS) pathologists register to be able to provide death investigation services in Ontario [2]. As stated in section 9 of the Act, a coroner may issue a warrant to perform a post-mortem examination of a body only to a pathologist who appears in the OFPS pathologists register [3].

Furthermore, in accordance with section 29(1) of the Act, a pathologist who performs the post- mortem examination of a body must immediately report – in writing – his or her findings from the post-mortem examination and from any other examinations or analyses that he or she has conducted to the coroner who issued the warrant, as well as the Chief Forensic Pathologist [4].

1.2 Admission of Expert Evidence and Opinion

Following the Goudge Inquiry, Justice Goudge strongly recommended that the criminal justice system and the actors therein subject forensic pathology evidence to a high degree of scrutiny and not simply accept it at face value. He emphasized that this may help to avoid erroneous or inappropriate testimony in future, which may decrease the number of wrongful convictions and miscarriages of justice resulting from flawed expert testimony [5]. Justice Goudge specifically referred to and encouraged courts to actively apply R v Mohan [6], which established a four-part test for the admission of expert evidence at trial. The test states that if a court is to admit and consider expert evidence at trial, then the party tendering the expert evidence must show on a balance of probabilities that it is (a) relevant to the case; (b) of necessity in assisting the trier of fact; (c) not subject to any exclusionary rule; and (d) being delivered by a qualified expert [7].      

Whether expert evidence is relevant is a question of law. If it is related to and helps to establish material facts, and if its probative value outweighs its prejudicial effect, then it may be considered relevant to the case [8]. Whether expert evidence is necessary depends on the outside experience and knowledge of a judge or jury. If the issues are technical and the court would be unable to come to a satisfactory conclusion without the assistance of an expert, then the evidence may be considered necessary [9]. Finally, if the expert evidence has a greater probative value than prejudicial effect and has been delivered by a qualified expert with special or peculiar knowledge acquired through study and experience, then Mohan is satisfied and the evidence is admissible.

Justice Goudge, however, has encouraged the courts to go even further and apply R v J.-L.J. [10] when assessing the admissibility of forensic pathology evidence at trial, even though this case typically applies to expert evidence deemed novel or unproven [11]. Justice Goudge supported this recommendation by referring to R v Trochym [12], where Deschamps J. stressed that the admissibility of scientific evidence – even recognized scientific evidence – is not frozen in time, as science is constantly evolving [13]. Justice Goudge therefore recommended that the courts subject forensic pathology evidence to even greater scrutiny by applying not only Mohan, but also J.-L.J. 

R v J.-L.J. established an additional four-part test to determine the reliability of expert evidence. Before a court can treat expert evidence as reliable and admissible, it must consider (a) whether the theory or technique has been tested; (b) whether the theory or technique has been subject to peer review; (c) whether the theory or technique has a known or potential rate of error; and (d) whether the theory or technique has been generally accepted [14] In following this test, a court may be able to gauge whether the theory or technique has been subjected to scrutiny by the scientific community. This can assist a court in uncovering the existence of substantive flaws, contradictory evidence, and negative reviews, all of which can affect reliability and admissibility.

1.3 Admission of Fresh Evidence

When new forensic pathology evidence given by one expert conflicts with forensic pathology evidence given by another at an earlier date, section 683(1) of the Criminal Code permits a court to accept the fresh evidence where it is in the interests of justice to do so [15]. Fresh forensic pathology evidence has been accepted in several cases to help overturn previous convictions, including R v Truscott, R v Mullins-Johnson, R v Marquardt, and R v Sherret-Robinson.

To be admissible, fresh evidence must satisfy certain criteria. First, it must be admissible under operative rules of evidence, particularly expert evidence rules. This means that fresh evidence must (a) be relevant; (b) be necessary; (c) have a higher probative value than prejudicial effect; and (d) be delivered by a qualified expert with special and peculiar knowledge [16].

Second, the fresh evidence must be such that were it adduced at the original trial, it could reasonably be expected to have affected the verdict. Courts must here assess several factors, such as whether the fresh evidence is (a) relevant in that it bears upon a decisive or potentially decisive issue at trial; (b) credible in that it is reasonably capable of belief; and (c) sufficiently probative [17].

The third and final component of the admissibility analysis examines any explanation offered for the failure to adduce the evidence at trial. The explanation, or the absence of one, is referred to as the due diligence inquiry. This inquiry is important because the integrity of the trial process and the finality of trial verdicts would be destroyed by the routine admission of evidence on appeal that could have been adduced at trial. If no adequate reason can be given, however, and if the previous criteria have been satisfied, then the fresh evidence now adduced is admissible [18].

1.4 Inappropriate Conduct by Expert Witnesses

In R v Taylor, forensic pathology evidence was found inadmissible because the expert witness – Dr. Currie – spoke definitively when giving his opinion. Dr. Currie had not examined the deceased but rather he examined photographs of her wounds. Despite this, he was adamant that all of the wounds were inflicted from behind in what he described as a homicidal attack. The trial judge ruled that Dr. Currie’s expert testimony was inadmissible because his definitive manner affected the reliability of his testimony [19]. Had Dr. Currie expressed a more modest opinion and stated that the wounds were consistent with an attack from behind, his expert opinion may have been admissible. But because he repeatedly stated that he had no doubt that the wounds were caused by a homicidal attack from behind, the trial judge found his evidence inadmissible.

Additionally, Dr. Currie referred to blood spatter evidence and testified that the height of blood spatter at the crime scene indicated that the victim was standing when attacked. The trial judge found this evidence inadmissible because it fell outside Dr. Currie’s area of expertise. The trial judge ruled that an expert must confine his opinion to his area of expertise, and that evidence regarding blood spatter is a matter for a blood spatter analyst and not a forensic pathologist [20]. 

In R v Kporwodu, charges of first-degree murder were ultimately thrown out because the pathologist who performed the autopsy on the victim – Charles Smith – considerably delayed the delivery of an addendum to his post-mortem report. Smith took roughly 8.5 months to deliver his 1.5 page addendum to the Court, and so the trial judge dismissed the charges in accordance with section 11(b) of the Canadian Charter of Rights and Freedoms, which states than an individual has a right to be tried within a reasonable amount of time [21]. When faced with this dilemma, courts must consider the length of the delay, the accused’s waiver of time periods, the reasons for the delay, and any prejudice to the accused as a result of the delay. Smith could provide no justification for the delay and so the trial judge had no choice but to dismiss the charges. In doing so, he ruled that Smith’s unnecessarily delaying his post-mortem report violated the accused’s right to security of the person, as it prolonged the accused’s exposure to criminal proceedings. The trial judge also found that the delay violated the accused’s right to liberty by increasing his time spent in pre-trial incarceration as well as his right to a fair trial, as the evidence in the case was no longer fresh [22].

1.5 Stomach Content Analysis and Time of Death

Stomach contents, as a determinant of time of death, was the central issue in R v Truscott. In 1959, Steven Truscott was convicted of the first degree murder of Lynne Harper after the latter’s stomach contents were used to narrowly define her time of death and place her in the company of the accused. In 2007, as part of a reference into the Truscott case, fresh evidence was adduced by a team of forensic pathologists who testified that stomach contents cannot be used to narrowly pinpoint a precise time of death. They gave evidence that stomach contents should not be used as probative evidence to pinpoint time of death, as several factors can affect the digestive process. These include state of health, age, gender, size, level of stress, and the size of the meal [23].

Moreover, one expert testified that the digestive process is measured using ordinary subjects in a controlled setting. He explained that the rate of digestion for a normal individual is incomparable to that of a victim experiencing increased fear, stress, and other emotions that may impact the digestive process. As a result, the Judge on Appeal ruled that stomach contents alone cannot be used to pinpoint a precise time of death, or even a limited period as to time of death because factors affecting digestion leave stomach content analysis prone to a reasonable doubt [24].

Similar testimony was provided in R v Ho, where a forensic pathologist tendered evidence that digestion analysis is uncertain, making stomach content analysis too unreliable to be used to determine time of death. The Judge on Appeal subsequently ruled that stomach content analysis is – on  its own – a controversial, uncertain, and unreliable method for estimating time of death [25].

1.6 Rigor Mortis, Livor Mortis and Time of Death

In R v Truscott, the same team of experts who refuted stomach content analysis as a reliable determinant of a person’s time of death also agreed that the extent of rigor mortis is not a reliable indicator of time of death, except within very broad parameters [26]. A similar position was taken in R v Liu, where a forensic pathologist led evidence that rigor mortis and livor mortis are unreliable indicators to pinpoint a precise time of death. The forensic pathologist did, however, estimate the victim’s time of death as falling within a broader, twelve hour time period. The Judge of Appeal accepted this time frame, but only because in addition to motive there was a wealth of powerful circumstantial evidence that incriminated the appellant. Taken together, the evidence supported the conclusion that the deceased was killed during the twelve-hour period [27].  

The available case law seems to support scientific literature which states that rigor mortis, livor mortis, algor mortis, stomach contents, and other time of death indicators are neither conclusive nor precise when considered on their own. Instead, they may be used to estimate a broad or initial time of death that can be altered and refined as other evidence becomes available.  


1 Coroners Act, supra note 63 @s 1(1)

2 Ibid @s 7.1(1)

3 Ibid @s 9

4 Ibid @s 29(1)

5 Inquiry into Pediatric Forensic Pathology in Ontario: Policy and Recommendation, vol 3 (Toronto: Ministry of the Attorney General, 2008) @p 475 [Goudge Report volume 3]

6 R v Mohan, 1994 CanLII 80 (SCC)

7 Ibid @para 17

Ibid @para 18

Ibid @para 22

10 R v J.-L.J., 2000 SCC 51 

11 Goudge Report volume 3, supra note 79 @p 484

12 R v Trochym, [2007] 1 SCR 239

13 Ibid at para 31

14 J.-L.J., supra note 84

15 Criminal Code, RSC 1985, c C-46 @s 683(1)

16 R v Truscott, 2007 ONCA  575 @para 92 

17 Ibid

18 Ibid

19 R v Taylor, 2001 BCSC 1025 @paras 3 & 9

20 Ibid @paras 14-16

21 Canadian Charter of Rights and Freedoms, Part I of the Constitution Act, 1982, being Schedule B to the Canada Act 1982 (UK), 1982, c 11 @s 11(b)

22 R v Kporwodu, 2003 CanLII 30947 (ONSC)

23 Truscottsupra note 87 @para 184

24 Ibid @paras 188 & 190

25 R v Ho, 1999 CanLII 3823  (ONCA)

26 Truscott, supra note 87 @para 150

27 R v Liu, 2004 CanLII 34061 (ONCA)