Police in a small community in central Ontario are investigating the deaths of four people as a triple murder-suicide.

Ontario Provincial Police announced on Sunday that they believe a man killed two women and another man before killing himself in Ryerson Township, Ont., about 300 kilometres north of Toronto.

Det.-Insp. Martin Graham said somebody stopped by the home on Friday evening and found "the tragic scene."

He said three of the dead were members of the same family and lived in the house where they were found.

"The fourth deceased in the residence is not related by blood to the three victims of the homicide, but is also a resident of Ryerson Township," he said.

He added that firearms were recovered from the scene, but wouldn't say whether any of the victims were shot. Police have not released the names of the dead.

The incident happened at a home that lies at the end of a rural road in the isolated community of just under 650 people.

Deputy Reeve Barbara Marlow said she hasn't heard of a tragedy of this scale happening in the township during the 45 years she's lived there.

"It's just a small community, so everybody is quite shocked," she said.

Cathy Still, the mayor of the nearby village of Burk's Falls where Ryerson's population does its socializing, said she too was surprised by the deaths.

"This is really strange. We've only had maybe four incidents in the last 60 years of anything involving shootings or guns, or anything like that."

Graham said police won't be commenting on any potential cause of death until a post-mortem is complete, which he said likely won't be until later in the week.