Man who killed parents in Montreal suburb to be detained in psychiatric hospital

A 31-year-old man will likely spend the rest of his life in a psychiatric institution for the killing of his parents in a Montreal suburb.

Mitchell Arnott has been found not criminally responsible for the double homicide and has been declared a high-risk accused, a designation reserved for those considered a serious threat to public safety.

In October 2022, he stabbed Wayne Arnott and Louise Boucher to death in their Île-Bizard home. He had been released from the psychiatric department at the Montreal General Hospital five days earlier.

Wayne Arnott was the owner of the Bluenose Collectibles shop in Pointe-Claire, Que.

In his ruling, the judge cited Mitchell Arnott's long history of mental illness, past violent behaviour and refusal to take his medication.

The ruling says two forensic psychiatrists determined that at the time of these events, the accused suffered from a mental illness described as schizoaffective disorder, mixed episode and treatment-resistant schizoaffective disorder with a psychotic episode.

Both the defence and prosecution believe that Mitchell Arnott should be designated a high-risk accused, conceding that there is a substantial likelihood that he will resort to violence that could endanger the life and safety of another, the ruling says.

He is also prohibited from contacting certain friends and family members. He will be confined to the Institut national de psychiatrie légale Philippe-Pinel in Montreal.