Case Studies On Coerced Confessions
Use of Forensic Evidence in Canadian Trials
Forensic evidence refers to the scientific techniques and methods used to investigate crimes and establish facts in a court of law. In Canada, forensic evidence can include:
DNA evidence
Fingerprints
Ballistics
Toxicology
Digital evidence
Forensic pathology
The admissibility of forensic evidence in Canadian courts is guided by the common law principles of relevance, reliability, and probative value, as well as statutory provisions under the Canada Evidence Act and the Criminal Code. The courts also assess whether the evidence could prejudice the jury, or if it is based on proper scientific methodology.
Key Canadian Cases Involving Forensic Evidence
1. R. v. Mohan, [1994] 2 S.C.R. 9
Facts: This is a landmark Supreme Court of Canada case concerning the admissibility of expert evidence, including forensic evidence.
Issue: Whether expert testimony based on forensic science is admissible.
Decision: The Supreme Court outlined a four-part test for admitting expert evidence:
Relevance to an issue at trial.
Necessity to assist the trier of fact.
Absence of exclusionary rules.
A properly qualified expert.
Significance: This case is foundational for forensic evidence. It ensures that forensic evidence must assist the judge or jury and is not simply to bolster credibility. It is frequently cited when determining if DNA or fingerprint evidence should be admitted.
2. R. v. Smith, [1992] 2 S.C.R. 915
Facts: The case involved forensic pathology to determine the cause of death.
Issue: The reliability of forensic pathology testimony linking the accused to the death of the victim.
Decision: The Court emphasized that expert medical evidence must be based on sound scientific methodology. In Smith, the pathologist’s conclusions were allowed because they were carefully derived from standard forensic techniques.
Significance: Reiterated the importance of methodology in forensic science. Forensic evidence cannot be speculative; it must be derived from established scientific principles.
3. R. v. J.-L.J., [2000] 2 S.C.R. 600
Facts: This case involved DNA evidence to identify the perpetrator of a sexual assault.
Issue: The admissibility of DNA evidence collected from the crime scene.
Decision: The Court allowed the DNA evidence, highlighting that modern DNA profiling is highly reliable and probative.
Significance: Established that DNA evidence has a high degree of accuracy and can be critical in linking a suspect to a crime scene, provided collection and testing followed proper protocols.
4. R. v. Mohanlal, 2002 BCSC 111
Facts: This case involved forensic ballistics in a shooting.
Issue: Whether the firearms expert’s testimony connecting the bullet to the accused’s weapon was admissible.
Decision: The Court admitted the evidence, noting that ballistics expertise can significantly assist the trier of fact when the methodology is sound.
Significance: Demonstrates that forensic evidence, when scientifically grounded, is a powerful tool in criminal trials.
5. R. v. Trochym, [2007] 1 S.C.R. 239
Facts: The accused was charged with murder, and the prosecution relied on digital forensic evidence, including emails and computer files.
Issue: Admissibility and reliability of digital forensic evidence.
Decision: The Supreme Court held that digital evidence is admissible if properly authenticated and not obtained in a manner that violates rights under Section 8 of the Charter.
Significance: Highlighted the growing role of digital forensics in Canadian trials and the requirement for proper collection to maintain integrity.
6. R. v. W.(D.), [1991] 1 S.C.R. 742
Facts: While not purely forensic, this case established the standard for assessing credibility and evidence consistency.
Issue: How forensic evidence interacts with witness credibility.
Decision: The Court emphasized that forensic evidence should corroborate other evidence but cannot replace the need for careful assessment of testimony.
Significance: Shows that forensic evidence is powerful, but it must be considered alongside all trial evidence.
Observations
Reliability is key: Canadian courts focus heavily on whether forensic evidence is derived from valid scientific methods.
DNA dominates serious crime trials: Since the 1990s, DNA has often been decisive in sexual assault and murder cases.
Expert testimony regulation: Mohan sets the standard for how experts (including forensic scientists) testify.
Emerging technologies: Digital forensics, cybercrime analysis, and even forensic accounting are increasingly relevant.
Admissibility vs. weight: Even if evidence is admitted, its weight depends on accuracy, methodology, and context.
Forensic evidence in Canadian trials is not just about science—it intersects with legal principles, Charter rights, and judicial discretion, ensuring that evidence is both reliable and fair for the accused. The above cases illustrate the diversity of forensic tools and the courts’ careful approach to admitting them.
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