It is “hundreds of billions of times more likely” that the DNA found on Guylaine Potvin’s body belonged to the man accused of her murder rather than to any other individual, we learned at Marc’s trial -André Grenon, Wednesday.
The day was devoted to the testimony of forensic biologist Caroline Paquet, who came to explain to the jury the nature of the DNA samples taken in this case.
Guylaine Potvin was murdered on April 28, 2000 in her apartment in Jonquière, in Saguenay–Lac-Saint-Jean, a case that caused a lot of noise at the time.
PHOTO PROVIDED BY THE SÛRETÉ DU QUÉBEC
Guylaine Potvin
DNA samples were taken from several places at the crime scene, that is to say on the body of the victim, on a t-shirt that she was wearing and on traces of blood taken from a belt and on a box of condoms found at the scene.
An unknown male profile emerged from these analyzes without it being possible to associate him with anyone.
However, twenty years after the events, thanks to surveillance which allowed Sûreté du Québec (SQ) investigators to recover a cup and two straws thrown by Marc-André Grenon, comparisons were finally able to be made between his DNA and that of found on these exhibits.
Multiple samples
The match between the DNA found on these items and several samples from the crime scene is “hundreds of billions of times more probable” in the case of Marc-André Grenon than for any other individual, we can read in a expert report in DNA biology presented in court on Wednesday.
Marc-André Grenon was arrested in connection with the crime more than twenty years after the events, in October 2022, and accused of having killed and sexually assaulted the young woman. He pleaded not guilty.
Caroline Paquet indicated on Wednesday that she had not taken the DNA samples herself at the time on the numerous pieces of evidence provided at the time by the police at the Laboratory of Judicial Sciences and Legal Medicine, where she has worked since 2005.
“I took over the entire file, all the expert reports issued, all the notes on the documents, all the results obtained, I rechecked the calculations and I certify what is in the report. “expertise,” she explained at the end of her testimony.
The cross-examination of Caroline Paquet by Marc-André Grenon’s lawyers is due to take place on Thursday.