Forensic science can be a powerful tool for determining the identity of perpetrators of crime, but used improperly it can also lead to wrongful conviction. Forensic error has been identified in many known cases of wrongful conviction in Canada.The contribution of forensic science to the phenomenon of wrongful conviction can come in two ways: faulty science and human error.

As scientific understanding progresses, we often find that identification methods that were once considered to be reliable are not as accurate as we once thought. An example of this is fingerprint evidence. It was once thought that a positive fingerprint match was indisputable evidence of the guilt of the accused. However, as knowledge increased, it became apparent that fingerprint identification is heavily dependent on the subjective assessment of the person conducting the comparison, and is therefore not as infallible as once thought.

Another aspect of forensic science which bears on wrongful conviction is the conduct of the investigating scientists themselves. A prominent Canadian example of this is the work of Dr. Charles Smith. Dr. Smith was a prominent pediatric pathologist, who testified in many criminal cases throughout his career, especially in cases involving the death of a child. Dr. Smith's examinations came under scrutiny when a number of cases in which he claimed that a child died as a result of "shaken baby syndrome" (which is caused by abuse) were found to have lead to wrongful conviction. Subsequently, the high prevalence of error led the Chief Coroner of Ontario to review all of Charles Smith's previous work. The report concluded that Dr. Smith had erred on 20 of the 44 cases which were investigated. While this is a prominent example, it illustrates the fallibility of forensic expert evidence and its role in wrongful conviction.

However, forensic science has also been a key factor in discovering and addressing cases of wrongful conviction. The best example of this is the success of the Innocence Project in the United States in using DNA evidence to exonerate wrongfully convicted individuals. To date, the Innocence Project in the United States has successfully exonerated 205 individuals through DNA testing.

[prepared by Moheb Tewfik, class of 2008]

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