Matthew de Grood was born in 1991 in Calgary, Alberta, Canada. He was the son of a senior Calgary police officer. De Grood attended the University of Calgary, where he studied psychology and was accepted into law school. In the weeks leading up to the incident, his behavior became increasingly erratic. He posted cryptic messages on social media and exhibited signs of paranoia and delusional thinking. Despite these warning signs, there was no formal diagnosis or intervention prior to the tragic events.

On April 15, 2014, during a house party in the Brentwood neighborhood of Calgary, de Grood fatally stabbed five young adults: Zackariah Rathwell, Jordan Segura, Kaitlin Perras, Joshua Hunter, and Lawrence Hong. The attack occurred shortly after midnight, and de Grood fled the scene but was apprehended by police a short time later. He was charged with five counts of first-degree murder.

During his trial, it was revealed that de Grood was experiencing a severe psychotic episode at the time of the killings, believing that his victims were supernatural entities threatening his life. On May 25, 2016, he was found Not Criminally Responsible (NCR) due to mental disorder and was committed to a secure psychiatric facility. Over the years, his case has been reviewed annually to assess his mental state and potential risk to public safety. As of December 2023, the Alberta Review Board denied his request for discharge, citing ongoing concerns about his risk to the public and the necessity for continued structured psychiatric care.