OTTAWA–Criminal courtrooms are no place for hypnotically induced memories, the country's highest court has ruled.
In a 6-3 ruling that will have broad implications, the Supreme Court of Canada said the 30-year practice of using evidence obtained from witnesses who have been hypnotized is unreliable and should not be allowed in criminal trials.
The split decision appears to make Canada the first country with an English criminal-law tradition to place a total ban on post-hypnotic evidence.
Britain, Australia and New Zealand don't rule it out, although they impose procedural safeguards. The rules in the U.S. vary from state to state.
The decision overturns the second-degree murder conviction of Stephen Trochym, a former Canada Post supervisor from Toronto who was found guilty in 1995 of slashing his girlfriend's throat with a breadknife. The decision calls for a new trial.
Key evidence in the case came from a neighbour who said, after being hypnotized, that she remembered seeing Trochym emerge from the victim's apartment the day after the slaying in 1992.
The witness first told police she saw Trochym emerging from Donna Hunter's apartment on a Thursday, but changed her statement to Wednesday after undergoing hypnosis to refresh her memories. That timing corresponded to the police's theory of how the killer may have returned to Hunter's apartment to rearrange her body and make it look like a sexual assault.
The neighbour's testimony was characterized as critical by prosecutors at the trial, but Justice Marie Deschamps, writing for the Supreme Court majority, said scientific evidence is contradictory and inconclusive on the use of hypnosis to enhance memory.
"At the present time there is no way of knowing whether such information will be accurate or inaccurate," said Deschamps. "Such uncertainty is unacceptable in a court of law."
The judgment leaves room for police to keep using hypnosis as an investigative tool. But they will have to gather other evidence to corroborate any leads they obtain, and can't use post-hypnotic testimony at trial.
Deschamps set her ruling in a wider context, noting the publicity generated in recent years by the wrongful murder convictions of Donald Marshall, David Milgaard, Guy Paul Morin and others. Post-hypnotic testimony was not an issue in those cases, but Deschamps said they illustrate a need to "carefully scrutinize evidence presented against an accused for reliability and prejudicial effect."
"The technique of hypnosis and its impact on human memory are not understood well enough for post-hypnosis testimony to be sufficiently reliable in a court of law," she wrote.
Justices Beverley McLachlin, Ian Binnie, Louis LeBel and Morris Fish agreed with Deschamps that "there is no way of knowing whether such information will be accurate or inaccurate."
Justice Louise Charron, who sided with the majority, said expert evidence could be brought in to provide context about the lingering effects of hypnosis.
But in a strong dissenting ruling, Justices Michel Bastarache, Rosalie Abella and Marshall Rothstein took the majority to task. "The sole evidence advanced before this court on the hypnosis issue was a handful of American cases in which the courts have opted for categorical exclusion. This is not a sufficient evidentiary foundation upon which this court should overturn a longstanding Canadian common law rule."
They said Trochym and his lawyers did not challenge hypnosis at the trial level, and there was not a strong enough factual basis to warrant the elimination of such a tool, especially since, as with other kinds of evidence, trial judges and juries can be alerted to its weaknesses.
"These sorts of potential frailties with memory, whether ordinary or hypnotically refreshed, are those that juries are quite capable of weighing."
The dissenting judges noted hypnosis is not exactly "novel science," having been used for 30 years to help memory retrieval. It is rarely admitted in court without a judge first assessing its relevance and reliability, and like other scientific evidence can always be assessed "through a case-by-case evaluation, in light of the changing nature of our scientific knowledge."
In the Trochym case, the six-judge majority did not explicitly absolve the defendant. They returned the case to the lower courts for a new trial – assuming the Crown feels the remaining evidence is strong enough for a second prosecution.
Bastarache, writing for the three dissenting judges, said prosecutors presented an overwhelming case for conviction at the first trial. He concluded the jury would have found Trochym guilty even without the hypnotically aided evidence.
Trochym was sentenced to life in prison with no parole for 10 years following his conviction in 1995.
He was freed on bail in 1999 because of inordinate delays in obtaining trial transcripts needed for his appeal, but returned to prison after the provincial appeal court upheld his conviction in 2004.
The issue of hypnosis was also raised during the appeal of Robert Baltovich, convicted of second-degree murder in 1992, two years after his girlfriend Elizabeth Bain disappeared from the University of Toronto's Scarborough campus.
Baltovich's lawyer James Lockyer, who also represents Trochym, urged the court to consider whether the jury should have heard from witnesses whose evidence was enhanced by hypnosis.
In 2004, the Court of Appeal ordered a new trial for Baltovich, which is scheduled to start in September.
With files from Canadian Press