By Nia Williams and Scott Haggett
CALGARY, Alberta (Reuters) - The son of a long-serving member of Calgary's police force was arrested on Tuesday after five people at a house party were stabbed to death in the worst mass murder in the city's history, Calgary's police chief said.
Three men were found dead at the scene and a man and a woman died in hospital after the attack at an off-campus party to celebrate the end of the university term. Police said the man, a student at the University of Calgary whose name will be released once charges are laid, was an invited guest.
He was arrested after being tracked by dogs following the killings in the early hours of Tuesday morning at a house in a suburban neighbourhood of the city of 1.1 million. Police are not looking for any other suspects.
"This is the worst mass murder in Calgary's history," Calgary Police Chief Rick Hanson told a news conference. "The scene was horrific."
Calgary had 22 murders in 2013, according to police statistics, up from 18 in 2012.
Police have not named the five victims, who were all in their early twenties and from Alberta.
The suspect is in custody and awaiting charges, likely to be first degree murder, which carries a life sentence without parole for 25 years.
Hanson said the suspect's father, a 33-year member of Calgary Police Service, and his wife were "absolutely devastated" and "heartbroken" by the killings.
Hanson said the suspect arrived at the party, obtained a large knife and targeted the victims one by one, stabbing them several times. There were about 20 people at the party at the time.
Officers were called to the house at about 1:27 a.m. local time to reports of a stabbing in progress.
Neither the suspect nor any of the victims were known to the police for previous incidents. Hanson said there was no indication of any dispute that precipitated the event, or that any alcohol or drugs were involved.
"Our thoughts and condolences go out to the families who have lost their loved ones in this senseless tragedy," said Elizabeth Cannon, president of the University of Calgary. "We are working closely with Calgary police to ensure everyone has the support they need."
(Editing by Chizu Nomiyama)