A trial is to begin today for a man charged after five young people were stabbed at a party where they were celebrating the end of the university school year. Matthew de Grood, 24, faces five counts of first-degree murder in what police have said is Calgary’s worst mass killing. He’s been in custody since shortly after the attack on April 15, 2014. Officers who were called to a home in the city’s northwest discovered three men already dead. A fourth man found stabbed on the front lawn and a wounded woman inside the house died in hospital.

Lawrence Hong, 27; Josh Hunter, 23; Kaitlin Perras, 23; Zackariah Rathwell, 21; and Jordan Segura, 22, were all killed.

The University of Calgary held a public memorial for the victims two weeks after the stabbings. Hunter, Hong and Segura all attended the university. Perras studied at Mount Royal University and Rathwell was a student at the Alberta College of Art and Design.

The trial is being heard by an out-of-town judge at the request of both the prosecution and defence, because de Grood’s father is a high-ranking city police officer and could be called to testify. A psychiatric review determined de Grood was fit to stand trial, because he understands the charges against him and is able to communicate with his lawyer.

He has been undergoing treatment at the Southern Alberta Forensic Psychiatry Centre since his arrest. Allan Fay, who represents de Grood, hasn’t ruled out a defence of not criminally responsible by reason of a mental disorder. Police have not said what they believe may have motivated the attack, but have revealed de Grood was invited to the party and mingled with guests before the stabbing.