Calgary police baffled at knife attack that leaves five students dead
Authorities baffled over lack of motive for knife rampage in Calgary against a group of students – the worst mass killing in city's history

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.