A judge will rule in January whether a man who fatally stabbed his parents and grandmother inside their Montreal apartment in March 2023 is criminally responsible for the crimes.

The Crown and defence lawyers submitted arguments this week in the case and both agreed that Arthur Galarneau was not criminally responsible due to his mental state at the time of the triple murder.

Background: • Three stabbed to death in Rosemont-La-Petite-Patrie; Montreal police arrest suspect • 19-year-old facing 3 counts of 2nd-degree murder in Rosemont deaths; police confirm family connection

Experts for both sides concluded he was suffering from schizophrenia.

Quebec Superior Court Justice Annie Émond says she’ll render a decision on Jan. 22.

Galarneau was facing charges of second-degree murder in t

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