The Quebec Court of Appeal ordered a new trial of a man convicted of killing three people because the trial judge provided inadequate instructions to the jury over the weight that should be given to post-offence conduct and because he failed to warn the jury that the testimony of the prosecution’s expert went beyond the bounds of his expertise.
The ruling, the second time in six years that the Quebec appeal court set aside a murder conviction and ordered a new trial because of testimony provided by psychiatrist Sylvain Faucher, highlights pervasive concerns about expert bias and examines the credence that should be given to post-offence conduct, according to criminal lawyers.
For as long as expert witnesses have been allowed to testify, expert bias has always been a concern. So too is the quality and reliability of their evidence.
Uneasiness over the disproportionate weight given to expert evidence too has raised alarms as has the acceptable bounds of conduct that counsel should observe when dealing with experts, be it in the preparation of experts’ reports and affidavits or in preparing experts to testify at hearings or trials.
Indeed, the courts are still grappling with the issues raised by expert witnesses in spite of jurisprudence clarifying and tightening the threshold requirements for admissibility, adding new requirements to ensure reliability, and stressing the role of the judge as a gatekeeper. That numerous jurisdictions across the country have in recent years provided explicit guidance over the duty of expert witnesses has not quashed questions.
“In our adversary process, we normally allow the parties to present their evidence so they are the ones who call in the experts, and we don’t want to interfere too much with the adversarial process,” noted Lee Stuesser, co-author of “The Law of Evidence.”