NOBODY at the scene of the tragic discovery could have predicted the problem that lay ahead. After all, how do you preserve evidence you don't even know you've collected?
That's the scenario that played out in January 1985 when Winnipeg police investigators combed through a storage shed where the frozen body of Candace Derksen, 13, had been found.
Their actions that day are now the focal point of a high-profile case in which a man whose DNA has since been linked to the killing is on trial.
Mark Edward Grant's defence lawyer, Saul Simmonds, immediately took aim Thursday at the way police conducted the investigation. The teen vanished on her way home from school on Nov. 30, 1984, triggering an exhaustive search that involved hundreds of volunteers.
Retired officer Ronald Allan admitted in cross-examination the scene could have been "contaminated" after police found the teen's frozen body, her hands and legs bound with twine.
He said investigators had no way of knowing at the time of scientific advances that were to come, allowing for forensic testing that would lead them to Grant more than two decades later.
Several officers walked through the shed and surrounding area, not wearing any protective clothing, masks or hair nets, as they collected about 40 exhibits, Allan told jurors. Those included seven strands of hair found on a wooden stump that have now been linked to Grant.
"While you realize today you may have been contaminating things, you wouldn't have realized that back in 1985?" Simmonds asked.
"As far as things like hair and skin, no, we wouldn't," Allan replied. Allan couldn't say how many different sets of hands touched the twine from which Grant's DNA was ultimately extracted using advanced scientific techniques.
Simmonds suggested there's no way of knowing who the many officers at the scene previously had contact with, implying the possibility material was transferred to the scene.
Simmonds asked Allan whether officers at the scene that day could have "coughed, sneezed... scratched themselves" while searching for evidence.
Allan said it was possible, but the passage of time means there is no way to specifically remember.