TORONTO — A gunman opened fire at a high school and a second location in an aboriginal community in northern Saskatchewan on Friday, leaving four dead and at least two injured, officials said.

Prime Minister Justin Trudeau said from Davos, Switzerland, that a suspect was in custody. Trudeau initially said five died, but police later corrected that to four.

“This is every parent’s worst nightmare,” he said. “The community is reeling.”

Kevin Janvier said his 23-year old daughter Marie, a teacher, was shot dead by the gunman. He said police told him that the gunman first shot two of his siblings before killing his daughter.

“He shot two of his brothers at his home and made his way to the school,” he said. “I’m just so sad.”

Marie was Janvier’s only child. He said he didn’t know if the gunman knew his daughter.

Trudeau said the shootings occurred at a high school and another location but did not release any information on the second location. School shootings are rare in Canada.

Royal Canadian Mounted Police Chief Supt. Maureen Levy said the gunman was arrested outside the school but declined to release details about him.

Levy said she wasn’t sure how many suffered injuries. The prime minister earlier described two injuries as critical.

“At the present time there are four individuals deceased,” Levy said.