Montreal Man Who Stabbed Parents, Grandmother, Declared Not Criminally Responsible A 19-year-old Montreal man, Arthur Galarneau, has been declared not criminally responsible for the stabbing deaths of his parents and grandmother. The decision was based on a joint submission from the Crown and defence, acknowledging Galarneau’s severe schizophrenia at the time of the incident. Psychiatrists confirmed his condition included delusions, hallucinations, and psychotic symptoms.

• Arthur Galarneau, 19, declared not criminally responsible for murder.
• Victims include his parents and grandmother.
• Incident occurred on March 17, 2023, following a 9-1-1 call.
• Galarneau suffered from schizophrenia, including delusions, hallucinations, and psychotic symptoms.
• Court accepted joint submission from Crown and defence.
• Trial took place in December 2025.