An expert who literally wrote the book on forensic pathology cast further doubt yesterday on the evidence used to convict Stephen Truscott in the 1959 murder of Lynne Harper.
Bernard Knight, a professor emeritus of forensic pathology and the author of a textbook for pathologists, said it was "ludicrous" for the coroner in the original case to set a narrow 30-minute time frame for death.
Dr. Knight was the final witness to testify at a review of Mr. Truscott's murder conviction before the Ontario Court of Appeal.
Dr. John Penistan, the now-deceased coroner, used Lynne's stomach contents to conclude the 12-year-old died between 7:15 p.m. and 7:45 p.m. on June 9, 1959.
The timing made the then-14-year-old Mr. Truscott the prime suspect, and he was convicted of murder and sentenced to death. He served nine years in jail before being released on parole in 1969.
Dr. Knight, who has taught at the University of Wales since 1980, said it's impossible to pinpoint an exact time of death, even with today's science.
"Any doctor who tries to pin time of death down to a half hour is uninformed or incompetent," he told the court.
Dr. Knight said there's little consensus among experts in determining time of death, partly because it's very rarely used.
Ninety per cent of autopsies aren't homicides, he said, and for those that are, time of death usually isn't an issue.
"When it is, there are better methods to determine time of death," he said.
Though forensic science has made great strides since the days when a hand was used to check the warmth of a corpse, Dr. Knight said the best an investigator can do is set an approximate five-hour time frame.
He said it was "suspicious" for the original coroner to set the time of death between 7:15 p.m. and 7:45 p.m., which fit into the exact window of opportunity for Mr. Truscott to commit the crime.
Dr. Penistan came to that conclusion based on undigested food and the level of decomposition in Lynne's body, two variables Dr. Knight said have great margins of error.
Dr. Knight told the court emotional distress is one factor that can greatly alter when the stomach empties its contents.
"I'm not saying it's useless, but the margins of error are so wide it has very little practical application," he said.
The Crown pointed out that Dr. Penistan acknowledged the limitations on stomach content analysis in his 1966 testimony. "He acknowledges them, but doesn't seem to apply them," Dr. Knight shot back, adding that Dr. Penistan stuck to his half-hour time frame.
Dr. Knight also said it was unusual for the body, which was supposedly exposed to temperatures in excess of 30 C for two days, to be have been so well preserved.
He said his experience in similar near-tropical temperatures showed the bodies decomposing in the first day.
Five Ontario Court of Appeal judges reviewing Mr. Truscott's conviction have heard conflicting testimony about the reliability of witnesses, the thoroughness of the investigation and the scientific methods used to pin the murder on him. Yesterday marked the last day of witness testimony. Crown and defence lawyers will make oral presentations of their arguments in January. A decision is expected in the spring of 2007.