A woman from Sri Lanka and her four children were stabbed to death in a home in Ottawa by a student who is also from Sri Lanka, the police said on Thursday. Another man living in the home was also killed, and the children’s father was hospitalized with injuries.

Investigators charged Febrio De-Zoysa, 19, a student who also lived in the home, with six counts of first-degree murder and one count of attempted murder. He was arrested shortly after the police received two emergency calls around 11 p.m. Wednesday requesting they come to the home, which is in a residential neighborhood, police officers said.

Ottawa’s police chief, Eric Stubbs, said at a news conference that the stabbings were the largest mass killing in the city, Canada’s capital, in at least three decades.

“I want to emphasize this was a senseless act of violence perpetrated on purely innocent people,” Chief Stubbs said. “I know our whole community is shocked and mourning this event.”

The victims were identified as Darshani Banbaranayake Gama Walwwe Darshani Dilanthika Ekanyake, 35, the mother of the four children; Inuka Wickramasinghe, a 7-year-old boy; Ashwini Wickramasinghe, a 4-year-old girl; Rinyana Wickramasinghe, a 2-year-old girl; and Kelly Wickramasinghe, a 2-month-old girl.