Marc-Andre Grenon guilty in 2000 murder, sex assault of Quebec college student

Marc-André Grenon was found guilty of murdering and assaulting Guylaine Potvin (Source: Sûreté du Québec/Handout)

A Quebec Superior Court judge on Tuesday described Marc-André Grenon as a morally and sexually depraved killer as he sentenced him to life in prison for the first-degree murder of Quebec junior college student Guylaine Potvin in 2000.

Justice François Huot addressed Grenon moments after a jury convicted him at the courthouse in Saguenay, Que.

"I want to make this clear: I only feel disgust and contempt for the actions you took on April 28, 2000," Huot told Grenon, who declined the judge's invitation to address the victim's parents, present in the courtroom.

"You are an individual, as I mentioned a few moments ago, who is completely devoid of morality. You are sexually depraved and a murderer."

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 Potvin.

The 12-person jury reached its decision less than three hours after beginning deliberations. Spectators in the packed courtroom could be seen hugging and wiping away tears after the verdicts were read.

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.

Huot did not hold back as he sentenced Grenon, describing the convicted killer as a coward who attacked a vulnerable victim while she was asleep with her teddy bear, and then went on to enjoy 22 years of undeserved liberty before his arrest.

"Tell me, accused, while you were abusing Guylaine, did you feel strong? Did you feel courageous? Did you feel like a man, a real one?" he asked. "What a demonstration of force. What a demonstration of courage. It’s absolutely disgusting."

Outside the courtroom, members of Potvin's family said they hoped she would be remembered for the qualities she embodied in life, rather than the manner of her death.

"The extreme violence she was a victim of was the opposite of what she incarnated: gentleness, calm, goodness and peace," said her mother, Jeannine Caouette.

The family said it was starting a foundation to honour Potvin, who had been studying special education and had been interested in humanitarian efforts.

During the trial, Grenon's lawyers admitted he killed the teenager with a belt that was found next to her body but argued her death was a burglary gone wrong. Crown prosecutor Pierre-Alexandre Bernard maintained Grenon, 49, strangled Potvin during a sexually motivated assault that began after he spotted her asleep in her bed — making her death a first-degree murder.

Potvin, 19, lived with two female roommates, also students, who were not home when the killing took place inside their Panet Street residence in Jonquière, now a borough of Saguenay, about 215 kilometres north of Quebec City.

A pathologist testified that the teenager had died of strangulation, with injuries that included blunt trauma to her head and shoulder, a bite mark on her left breast, and injuries to her genital area.

While male DNA was discovered at the crime scene, the trial heard there was no match in the police database and no witnesses to the crime.

Police arrested Grenon in 2022 after following him to a movie theatre and collecting his discarded drinking straws. DNA on the straws was found to match the DNA from the crime scene, including under Potvin's fingernails, on a T-shirt she was wearing and on a box of condoms found at the scene. That match was confirmed when investigators obtained a warrant for a second DNA test after Grenon's arrest.

The defence argued Grenon had killed Potvin in a struggle after breaking into the apartment to commit robbery, and that any sexual contact took place after the victim had died. Defence lawyer Karine Poliquin suggested a second-degree murder conviction. Grenon did not testify during the trial, and his lawyer did not call any other witnesses.

The Criminal Code defines first-degree murder as “planned and deliberate," but a murder is also first-degree if it occurs in the course of a sexual assault. First-degree and second-degree murder come with automatic life sentences, but with first-degree murder there is no possibility of parole for 25 years. With second-degree murder, parole eligibility can be set at as little as 10 years.

During his final instructions to the jury, Huot said that, contrary to what the defence argued, it was not necessary to prove the sexual assault took place before the death, but only that an assault or attempted assault occurred in the same sequence of events as the killing.

The jury did not hear that Grenon, of Granby, Que., east of Montreal, is also charged with attempted murder and sexual assault in connection with a case in the provincial capital just months after Potvin's killing.

Police said their investigation into Potvin's murder turned up similarities with the Quebec City case from July 2000, in which a female student, living alone, was assaulted and left for dead but survived the attack.

Grenon's arrest was the first made by the provincial police's cold case squad since it was beefed up with more resources in 2018.

Huot, in conclusion, congratulated the investigators who tracked down the suspect, adding that other assailants "will sleep less well tonight after hearing this news."

This report by The Canadian Press was first published Feb. 20, 2024.