A 17-year-old is facing four counts of first-degree murder following a mass shooting in an indigenous community in northern Canada.
The teen, whose identity cannot be revealed under Canada's youth justice system, is also facing seven counts of attempted murder and one count of unauthorised possession of a firearm, officials with the Royal Canadian Mounted Police (RCMP) said on Saturday.
Friday's shooting rampage in La Loche, in northern Saskatchewan, could be one of the worst school shootings in Canadian history, RCMP Superintendent Grant St Germaine told reporters on Saturday.
"The days and weeks are going to be difficult as we come to terms with the impact of what has happened in our community," St Germaine said.
"It's a sad and difficult time and no words will take away the pain and sorrow of what has happened."
The victims have been identified as two teachers, Marie Janvier, 21, and Adam Wood, 35, and brothers Dayne and Drayden Fontaine, aged 17 and 13 respectively.
Seven others were wounded in the violence on Friday in La Loche, a Dene First Nations community with a population of about 3000, about 860 kilometres northwest of provincial capital Regina.
The suspect is expected to make his first court appearance next week.
St Germaine said that authorities received calls from teachers and students at the La Loche Community School on Friday at 1pm local time about a gunman "discharging a firearm at people in the school".
Police tracked down the suspect and pursued him through the school, eventually taking him into custody about 1.15pm. No one was injured during the arrest, St Germaine said.
Police then went to a home a couple of blocks away, where the Fontaine brothers were found dead.
Police cordoned off both locations on Saturday, as specialised investigators gather evidence.
St Germaine said police are not aware of any motive.
The worst school shooting in Canadian history happened on December 6, 1989 in Montreal's Ecole Polytechnique engineering school, where a gunman killed 14 female students and a university employee, and injured another 13 women, before taking his own life.
