The son of a Calgary police officer was charged in the fatal stabbing of five people at a house party that 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 shortly after 1 am on Tuesday, said police Chief Rick Hanson.
De Grood, 22, was charged with five counts of murder.
"This is the worst murder — mass murder — in Calgary's history," Hanson said. "We have never seen five people killed by an individual at one scene. The scene was horrific."
Canadian television named the victims as Lawrence Hong, Kaitlin Perras, Jordan Segura, Josh Hunter and Zachariah Rathwell. Hanson said their ages ranged from 22 to 27 and they were all "good kids".
Hanson said the motive for the attack was unknown.
Neither the victims nor the suspect had any prior problems with police, Hanson said.
Hanson said about 20 people were at the party celebrating the last days of classes at a home in Brentwood, near the campus. He said the suspect was invited to the party, showed up after working his shift at a grocery story and was welcomed.
He said it appears that the attack, which took place shortly after 1am on Tuesday, caught everyone by surprise.
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.
He said the suspect allegedly brought a weapon from work to the party, but also grabbed a large knife from inside the house.
Police said de Grood was arrested with the help of the police dog unit about 40 minutes after the stabbings and was taken to a hospital for treatment for dog bites.
Hanson said there was nothing to indicate the suspect was drunk or had taken drugs.
He said police were interviewing witnesses.
The blue-sided house where the stabbings occurred is on a quiet, tree-lined residential street. It was surrounded with yellow police tape as medical examiner staff brought three bodies out on stretchers.
Neighbour Doug Jones said about a dozen students had been drinking beer in the back yard earlier in the night, but they were not rowdy. He said they were talking about politics and the stock market. They took the party inside at about 9pm 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 on Monday. The event is an annual outdoor party on the campus featuring live music and beer gardens to celebrate the end of classes.
On Twitter, many students wrote about how they starting drinking on Monday morning and, when the campus event ended in the afternoon, they continued at parties elsewhere.
On Tuesday, about 500 students and faculty members attended a late afternoon vigil at the University of Calgary.
With a candle projected on a giant screen, university president Elizabeth Cannon called for a moment of silence.
"The world lost five bright, promising, beautiful young people," she said. "We are still coming to grips with this tragedy and what transpired. We don't know all the details and we don't know the full impact on our University of Calgary community."
Calgary mayor Naheed Nenshi called it tragic and urged people to support one another.
"Our community has been dealt a grievous blow. We've lost five young people, five good young people who did nothing wrong. Who like all of us had dreams and hopes and were building their lives," Nenshi said.
The attack came nearly a week after a teenage boy in the US stabbed and wounded 21 students at his high school outside Pittsburgh.