Man who killed Quebec student in 2000 pleads guilty to separate attempted murder

Marc-Andre Grenon was arrested on Wednesday, Oct. 12, 2022, in the death of 19-year-old Guylaine Potvin, who died in 2000 in Jonquiere, Que. (Source: Surete du Quebec)

The man who was convicted earlier this year in the first-degree murder of a Quebec junior college student in 2000 has pleaded guilty in a second cold case.

Marc-André Grenon admitted Friday to attempting to murder a woman who was found assaulted and left for dead in Quebec City in July 2000, months after police discovered the body of Guylaine Potvin about 180 kilometres north.

Prosecutor Pierre-Alexandre Bernard said outside the courtroom that Grenon pleaded guilty in the second cold case because of the "strong and convincing evidence" against him, including his DNA found at the scene of the crime.

Bernard paid tribute to the "courage, determination and perseverance" of the victim over the more than 20 years she waited to see justice.

"We sincerely hope that the final and definite closure of the cases involving Marc-André Grenon today will allow her to turn the page and aspire to live more freely," he said.

In February, a jury took less than three hours to convict Grenon of sexually assaulting and fatally strangling 19-year-old Potvin after he broke into her Saguenay, Que., apartment while she was sleeping. Justice François Huot described the killer as "completely devoid of morality," as well as "sexually depraved and a murderer" as he sentenced Grenon to life in prison with no possibility of parole for 25 years.

Investigators had honed in on the suspect more than 22 years after the two crimes when a project tracking Y chromosomes — which are passed down from father to son — suggested the previously unidentified DNA left by Potvin's killer was connected to the last name Grenon.

Police arrested Grenon in 2022 after following him to a movie theatre and collecting his discarded cup and drinking straws, which were used to analyze his DNA and confirm the match to the murder.

The investigation into Potvin's murder turned up similarities with the Quebec City case, in which a female student, living alone, was assaulted and left for dead but survived the attack. Grenon's DNA was found at the scene of both crimes.

Bernard said Grenon was sentenced to 15 years in prison, which he will serve at the same time as the 25-year sentence for Potvin's murder.

Grenon's lawyers have dropped their appeal of his first-degree murder conviction, which means the cases against him are closed, he added.

This report by The Canadian Press was first published June 7, 2024.