Quebec police officer sat beside cold case suspect in movie theatre to get his DNA, trial hears

A Quebec provincial police investigator on Thursday recounted how he and his partner tracked the man suspected of killing Guylaine Potvin, a 19-year-old slain in Saguenay nearly 24 years ago, to a cinema and discretely recovered some of his DNA.

Det. Sgt. Christian Royer testified on Thursday morning at the trial of Marc-Andr Grenon, who is accused of first-degree murder and aggravated sexual assault.

The alleged crimes were committed in April 2000, in Jonquire, today a borough of Saguenay.

Royer told the jury how he and his partner staked out Grenon's apartment in Granby, in August 2022, after the Laboratoire de sciences judiciaires et de mdecine lgale du Qubec had identified him as a possible person of interest in Potvin's death.

Potvin was found dead at her home in April 2000. She had been sexually assaulted and strangled.

While outside Grenon's apartment, trying to confirm his address, Royer and his colleague saw him get into the passenger seat of a vehicle driven by a woman. They decided to follow him.

"Since the goal was to recover DNA, we thought we'd follow them to see where they were going," he testified at the trial.

From there, Royer and his partner followed Grenon and his companion to a cinema, where the policeman bought a ticket for the same film, which had assigned seats.

The last available seat in the section where Grenon was seated was directly to his left. While his colleague sat by the nearest trash cans, Royer spent the two hours of the film less than a metre from Grenon, watching him sip his drink and checking to see if anyone else was touching the cup.

"I don't have to tell you, I wasn't very absorbed in the film," he said in court, provoking laughter.

Royer recounted that he and his partner then followed Grenon out of the cinema, where they saw him throw his soft drink cup in the garbage can. The officer said he fished it out after putting on gloves, and sent it for DNA testing.

The Crown has previously said that the accused became a person of interest in the case in 2022 after a database linking DNA to male surnames suggested that the sample taken from the crime scene could be linked to the name 'Grenon'.

Crown lawyers have said Grenon was arrested after DNA collected from the cup and straws at the theatre were found to match the previously unidentified male DNA collected at the crime scene more than 20 years earlier.

Earlier Thursday, the jury learned that Grenon had been described in 2001 as a "person of interest" in the crime because he had previously lived in a building behind the residence where Potvin lived.

Grenon, 49, pleaded not guilty. On cross-examination, Royer told the defence that he had not taken any photos of the suspect holding the drink or sitting in the cinema. He also acknowledged that the evidence bag had been mislabeled as containing one straw, not two.

The trial resumes Monday.