SAGUENAY, Que. — A Quebec police officer described for a jury on Thursday how he and his partner tracked a suspected killer to a movie theatre, where the officer sat in the seat next to the suspect for nearly two hours before secretly taking his discarded soft drink cup for a DNA test.
Provincial police Sgt.-Det. Christian Royer took the stand in the Saguenay, Que., trial of Marc-André Grenon, who is charged with the first-degree murder and aggravated sexual assault of Guylaine Potvin in April 2000.
Royer said he was sent to Grenon's apartment in Granby, east of Montreal, in August 2022 after the province's forensics lab identified him as a possible person of interest in the 19-year-old's death.
While he was originally only asked to verify Grenon's address, Royer and his partner saw him get into the passenger seat of a vehicle driven by a woman and decided to follow.
"Since ultimately the goal was to recover DNA, we said to ourselves, we'll follow them to see where they go," he told the trial.
From there, Royer and his partner followed Grenon and his companion to a cinema, where the officer purchased a ticket for the same movie, which had assigned seating.
He said it turned out that the last available seat in Grenon's section was directly on Grenon's left. While his partner stationed himself near the closest garbage cans, Royer spent the next two hours less than a metre from Grenon, watching him sip his drink and checking to see if anyone else touched the cup.
"I don't have to tell you, I wasn't very absorbed in the movie," he told the courtroom, drawing laughs.
Royer said he and his partner followed Grenon out of the theatre, where they watched him throw his soft drink cup in the garbage. The officer said he donned gloves and fished it out, and it was bagged as potential evidence and later sent for DNA testing.
Potvin was found dead in April 2000 in her apartment in Jonquière, now part of Saguenay, 215 kilometres north of Quebec City. A pathologist concluded she'd been sexually assaulted and strangled to death.
The Crown has previously said the accused became a person of interest in the case in 2022 after a database that links DNA to male surnames suggested the sample collected at the crime scene might be connected 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.
A second officer, Pierre-Antoine Côté, described arresting Grenon in Granby on Oct. 2. The suspect was then taken to Montreal, where a warrant had been issued for fingerprinting, a dental imprint test and a new DNA test, testified Côté, who added that Grenon was co-operative.
Earlier Thursday, the jury learned that Grenon had been cited in 2001 as a "person of interest" in the crime because he had previously lived in a building behind the residence where Potvin lived and was killed.
Grenon, 49, has pleaded not guilty. On cross-examination, Royer told the defence that he didn't take photos of the suspect holding the cup or sitting in the theatre. He also acknowledged that the evidence bag had been mislabelled as containing one straw, not two.
The trial resumes Monday.
This report by The Canadian Press was first published Jan. 25, 2024.
— By Morgan Lowrie in Montreal
The Canadian Press
