2014 Calgary stabbing

On April 15, 2014, at approximately 1:20 a.m., an attack occurred at a house party at 11 Butler Crescent in the Brentwood neighbourhood of Calgary, Alberta, several blocks from the University of Calgary campus. The gathering, held to mark the end of the school year, had about thirty people in attendance. Matthew de Grood, an invited guest who was later found not criminally responsible, obtained a large knife at the house shortly after arriving and stabbed each victim multiple times. He fled on foot and was arrested by police 40 minutes later with the aid of a K-9 unit. This incident has been described as the deadliest massacre in Calgary's history.

The five victims were Joshua Hunter, Kaitlin Perras, Jordan Segura, Lawrence Hong, and Zackariah Rathwell, ranging in age from 21 to 27. Hunter lived in Priddis, Alberta, while the other four lived in Calgary. Hong, Segura, and Rathwell were pronounced dead at the scene; Perras and Hunter died later in hospital.

Matthew de Grood, aged 22 at the time, was a Safeway employee and University of Calgary student who had planned to attend law school. He is the son of a Calgary Police inspector, Doug de Grood. Authorities said de Grood personally knew at least one person present at the party. According to his parents and classmates, his behaviour had begun to change in the weeks before the stabbings, including more frequent and "bizarre" Facebook postings. Hours before the killings he posted the title of a Megadeth song, and he had earlier sent text messages to his parents claiming he intended to harm himself. At arrest, he was found with garlic in his pocket, which he told police was meant to "keep zombies away," though he had also posted online about killing vampires.

De Grood was charged with five counts of first-degree murder and ordered to stand trial. On May 22, 2015, he was found mentally fit to stand trial following a psychiatric assessment. His trial was scheduled to begin May 16, 2016. On May 25, 2016, de Grood was found not criminally responsible for the homicides on account of a mental disorder—diagnosed by two of three expert witnesses as schizophrenia—that caused a psychotic episode during the killings. His lawyer, Allan Fay, stated that de Grood intentionally killed the five victims while believing they were werewolves and vampires threatening his life. The finding means de Grood is held in a psychiatric facility subject to periodic reviews that could eventually permit conditional release. He has told the Alberta Review Board that he wishes the "terrible tragedy" had never happened. In September 2019, the Alberta Review Board granted him unsupervised outings while noting he "remains a significant risk to the safety of the public." In December 2023, the Alberta Criminal Code Review Board refused a request for his discharge, citing ongoing risk concerns and the need for continued structured psychiatric care.

The University of Calgary, though the stabbings occurred off-campus, responded directly given close ties between those involved and the university community. University president M. Elizabeth Cannon called the event a "senseless tragedy." The university later held commemorative events, and posthumous degrees and memorial scholarships were established for several of the victims.