CALGARY, Alberta — The son of a Calgary police officer was charged in the fatal stabbing of five people at a house party that law enforcement officials called the worst mass slaying in the western Canadian city’s history.
Matthew Douglas de Grood, a recent graduate of the University of Calgary, picked up a large knife shortly after arriving at the party and stabbed the victims one by one shortly after 1 a.m. Tuesday, said police Chief Rick Hanson.
De Grood, 22, was charged with five counts of murder late Tuesday.
‘‘This is the worst murder — mass murder — in Calgary’s history,’’ Hanson said at a press conference Tuesday. ‘‘We have never seen five people killed by an individual at one scene. The scene was horrific.’’
The Calgary attack came nearly a week after a teenage boy in the United States stabbed and wounded 21 students at his high school outside Pittsburgh.
Hanson said the motive for the Calgary attack was unknown. He said the suspect’s father and mother are devastated.
‘‘They are now feeling so much sorrow,’’ he said. ‘‘Those young people are dead and they are absolutely devastated.’’
Hanson said the identities of the five victims — four men and a woman — will be released when autopsies are completed. He said their ages range from 22 to 27 and they were all ‘‘good kids.’’
Neither the victims nor the suspect had any prior involvement with police, Hanson said.
The University of Calgary said de Grood graduated in 2013 with a bachelor’s degree, majoring in psychology with a minor in law and society.
Hanson said about 20 people were at the party celebrating the last days of classes at a home in the residential neighborhood of Brentwood, near the campus. He said the suspect was invited to the party and showed up after working his shift at a grocery store and was welcomed inside.
He said it appears that no one at the party had been sleeping when the attack took place shortly after 1 a.m. Tuesday.
Hanson said the suspect ‘‘targeted the victims one by one, stabbing them several times.’’
‘‘Was there anything that precipitated the event? Was there something that anyone had done that anyone could have taken as an insult or an affront to this individual? To the best of our knowledge right now, there’s nothing to indicate anything like that happened,’’ Hanson said.
Hanson said the suspect allegedly brought a weapon from work to the party, but grabbed a large knife from inside the house.
Three men were found dead at the home after someone at the party called the emergency dispatcher. A man and a woman died at a hospital.
Police said de Grood was arrested with the help of the police canine unit about 40 minutes after the stabbings and was taken to a hospital for treatment of dog bites.
Hanson said there’s nothing to indicate the suspect was drunk or had been doing drugs.
He said police are interviewing witnesses.
The blue-sided house where the stabbings occurred is on a quiet, tree-lined residential street.
Neighbor Doug Jones said about a dozen students had been drinking beer around a fire pit in the backyard earlier in the night, but they weren’t rowdy. He said they were talking about politics and the stock market. They took the party inside at about 9 p.m. and he heard nothing after that.
Other residents in the area said the house party stemmed from the student union’s annual Bermuda Shorts Day, which was held Monday. The event is an annual outdoor party on campus to celebrate the end of classes.