It has been 33 years since Diane Werendowicz was dragged into a ravine, allegedly sexually assaulted, strangled and dumped in a creek in the Hamilton area.
Robert Badgerow was arrested in 1998 and was convicted of first-degree murder several years later, but the verdict was overturned on appeal.
Ontario's Appeal Court ordered a new trial, but the second trial ended in a mistrial, with the jury unable to reach a verdict, and the third trial also ended in a mistrial.
A Superior Court judge ordered a stay, which would have effectively ended the case against Badgerow, but in a ruling released Tuesday the Appeal Court overturned it and ordered Badgerow to stand trial for a fourth time.
The Appeal Court says "highly probative and admissible evidence" was excluded at the previous trials, so the Crown hasn't had a full opportunity to put its case before a jury.
There is a risk of "undermining the integrity of the justice system" by prosecuting Badgerow for a fourth time, but the court must balance that against the societal interest in a final decision on the merits of the case, the judges wrote.
"Notwithstanding the challenges associated with conducting a trial after the passage of almost 35 years, there is a strong public interest in a trial on all the legally admissible evidence and this swings the balance against a stay," the Appeal Court wrote.
Matthew Gourlay, one of Badgerow's lawyers, said he could find almost no cases across Canada in which the courts have allowed a person to be tried four times.
"It's extremely rare," he said in an interview.
"There's sort of a consensus view among most courts that more than three tries at convicting a person for the same offence stretches the bounds of fairness."
Now, after so many years since Werendowicz was killed, it will be difficult for both sides to present their cases, as a number of witnesses have since died.
Gourlay said he will have to fully review the Appeal Court ruling before deciding whether to seek leave to appeal to the Supreme Court of Canada.
Badgerow, who had been arrested in 1981 in connection with the "brutal assault" of a young woman in the same area, was identified as a suspect in Werendowicz's killing in the late 1990s, the Appeal Court wrote.
Police surreptitiously obtained a sample of Badgerow's DNA and it matched the profile from semen found in Werendowicz's body, the Appeal Court wrote.
At his trials, Badgerow maintained he had consensual sex with Werendowicz in the back of his truck at a bar the night she died and that someone else must have attacked her on her way home.
The evidence that was previously excluded from the trials that the Crown wants to introduce at a fourth trial is regarding a 911 call from a payphone, possibly placed by the killer and traced to a location near Badgerow's workplace.
Badgerow would be able to challenge the reliability of the trace of the 911 call and the evidence about his proximity to the telephone booth at the time of the call, the Appeal Court wrote.