A jury has found Marc-André Grenon guilty of first-degree murder in the 2000 death of Quebec college student Guylaine Potvin.
Mr. Grenon, who was arrested in 2022 after DNA on his discarded drinking straws matched evidence from the crime scene, was also found guilty of sexually assaulting the 19-year-old Ms. Potvin.
The verdicts were reached less than three hours after the jury began deliberations on Feb. 20 at the courthouse in Saguenay, about 215 kilometres north of Quebec City.
Police had honed in on the suspect more than 22 years after the crime when a project tracking Y chromosomes—which are passed down from father to son—suggested the DNA left by the killer was connected to the last name Grenon.
Mr. Grenon’s lawyers had admitted he killed the teenager in Jonquière, Que., now part of Saguenay, but argued that her death was a burglary gone wrong and that any sexual contact took place after the victim died.
Crown prosecutor Pierre-Alexandre Bernard maintained Mr. Grenon, 49, killed Ms. Potvin during a sexually motivated assault that began after he spotted her asleep in her bed—making her death a first-degree murder.
