Detective Sergeant Christian Royer took the jury along on the surveillance operation that allowed authorities to obtain the DNA of Marc-André Grenon, suspected of the April 2000 murder of Guylaine Potvin.
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The jury learned on Thursday morning that the name Marc-André Grenon had been in circulation for several years in the case of the murder of Guylaine Potvin.
Photo provided by SQ
The Crown and defense made an admission that in 1995 Grenon lived on Rue de Bretagne, directly behind the victim's apartment. Then he was still in the region at the time of the murder, having been arrested by police in Chicoutimi three days before the young woman's death.
At the start of his testimony, Detective Sergeant Christian Royer confirmed that Grenon was ultimately targeted “as a 'plus-plus' subject of interest” in the investigation into the murder, thanks to the PatronYme project's genealogical analysis.
In the cinema
This brings us to August 2nd, 2022.
The police officer and his partner drove to Granby early in the morning to monitor Marc-André Grenon's apartment on Rue Laval Sud. The goal is then to recover his DNA “by leaving behind an item that belongs to him.”
If nothing is reported during the day, the arrival of a black Honda Accord in the parking lot at 6 p.m. wakes investigators from their torpor. Grenon then leaves his accommodation and sits in the passenger seat next to the driver.
The police officers Royer and Salois, each in their respective vehicles, decide to follow the car, which will eventually stop at the Cinéma Élysée. Here, 22 years after the opening, the investigation into the death of Guylaine Potvin will reach its climax.
Close to the goal
Christian Royer took his seat to the left of Marc-André Grenon in the last row of Hall 3 of the cinema. Throughout the film, he will jealously pay attention to the suspect's glass of soft drink and the two straws inside.
“I was about a meter away from the glass,” the police officer said Thursday morning. “I can tell you I wasn’t really engrossed in the movie.”
After two hours, Royer states with certainty that no one else touched Marc-André Grenon's glass while he was watching him, but that he actually took three sips of his soft drink.
“I’m one step behind him.”
The bulk of the work then remains to be done, namely the recovery of the glass in question. At the end of the film, investigator Royer closely follows the suspect and the woman accompanying him, while his partner stands right next to the room's trash can.
Provided by the court
However, the suspect passes by without throwing his glass.
However, Grenon deviates from his route before going out and goes to a trash can “somewhat isolated, along a large pillar.”
“When he put the glass in, I was stuck behind him. I'm one step behind him,” testified the police officer, who made sure no one else followed and contaminated the precious glass.
Provided by the court
Part P83057
He then managed to recover the famous glass of soft drink and the two straws that made it possible to allegedly link Marc-André Grenon to the murder of Guylaine Potvin after 22 years of unsuccessful investigations.
Provided by the court
Packaged in a sealed bag, this critically important evidence to investigators, Exhibit P83057, was sent to the Forensic Science and Forensic Medicine Laboratory the next day for analysis.
The results of that analysis will be presented to the jury next week during testimony from two forensic biology experts. These two witnesses will conclude the testimony of the prosecutor, Me Pierre-Alexandre Bernard.
It is then the defense's turn to present their evidence to the jury, who will decide the fate of Marc-André Grenon.
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