A Montreal man who stabbed his parents and grandmother to death has been declared not criminally responsible for the crime.
The man, Arthur Galarneau, was 19 years old when he was charged with three counts of second-degree murder after Montreal police responded to a 9-1-1 call made on March 17, 2023, by Galarneau’s mother and found the three individuals had been stabbed to death.
Quebec Superior Court Justice Annie Emond said she agreed with a joint submission from the Crown and defence that was presented during a two-day trial in December 2025.
At the time of the incident, Galarneau was suffering from schizophrenia and his condition included delusions, hallucinations, and psychotic symptoms. Psychiatrists recommended that he be found not criminally responsible.
“This verdict means that Mr. Galarneau’s mental state was so disturbed that he lacked the capacity to rationally decide whether killing his family members was morally wrong or to fully grasp the nature and quality of his actions,” Emond said on Jan. 22.
She added that this meant he could not be held responsible for the deaths.
Emond read out details of the case, noting that Galarneau’s mother had called 9-1-1 around 9 a.m., requesting an ambulance to the Rosemont–La Petite-Patrie neighbourhood and saying “my son wants to kill me.”
Montreal police responded to the call, which had been traced, and could see through the window that someone had been stabbed, noting there was a lot of blood on the ground. Galarneau stabbed his family members Mylène Gingras, 53, Richard Galarneau, 53, and Francine Gingras-Boucher, 75, a total of 212 times.
Police kicked in the door and ordered Galarneau to stop, but he did not comply with police orders to lay down and police used pepper spray to try and subdue him. Galarneau spat on officers and tried to bite them. He also made comments about the devil and asked police to kill him.
The court heard that his mental health problems appeared when he was 16 years old in 2020. At that time, he was having delusions about a parasite and was diagnosed with schizophrenia and put on medication.
The Crown says it will be seeking a high-risk offender status for Galarneau. The status would require detention in a psychiatric facility and superior court oversight to any changes of his detention plan.
The defence said it would contest such a status being imposed on Galarneau.
Emond ordered a psychiatric evaluation for Galarneau in relation to the Crown’s request. The case is expected back in court on Feb. 23.
