An Ontario Provincial Police cruiser blocks the scene of what police are investigating as a triple murder-suicide about 300 kilometres north of Toronto, in Ryerson Township, Ont., on Sunday, February 25, 2018. THE CANADIAN PRESS/Salmaan Farooqui

A man whose mother, brother and grandmother died in what Ontario provincial police are calling a triple murder-suicide said Monday that his loved ones were killed by a neighbour who had been "stalking" his parent.

Thomas Theoret said his mother Ulla Theoret, 55, brother Paul Theoret, 28, and his grandmother Raija Turunen, 88, were found dead at their rural home in Ryerson Township, Ont., on Friday evening. Police have confirmed the identities of the three members of the same family, but have not said why or how they were killed.

Investigators also said 58-year-old Mark Jones was found in the same home. Police have said they believe Jones killed the three others before taking his own life.

Thomas Theoret, who was travelling to the small community about 300 kilometres north of Toronto to deal with the deaths, said Jones and his mother had known each other for a while before their relationship soured.

"My mom didn't really date (Jones) but I think they were just friends for a couple months," he told The Canadian Press. "Then he started acting kind of strange and kind of stalking her."

Theoret said one of his other brothers, who lives in another Ontario community, eventually told Jones to leave the family alone.

The interactions between Jones and the family took place over a year ago, he said, noting that his mother and the man started talking after Jones settled in the neighbourhood.

"My mom and dad had just got divorced and she was single, she was a little bit distraught. She was looking for friends and this guy Mark Jones moved into the area," Theoret said. "He was kind of a handyman and my grandma liked him because he helped fix a few things around the house."

The bodies of Theoret's family members and Jones were found by a friend who stopped by the home for a pre-arranged visit around 7:30 p.m. on Friday, police have said, noting that the deaths took place sometime between Wednesday evening and the time of the discovery.

Officers have been combing the Theorets' house and a second home on the same street on Monday, looking for anything that could help them figure out how and why the killings happened.

"Obviously the only people who know exactly what happened and why it happened are unable to speak," said Det.-Insp. Martin Graham of the Ontario Provincial Police.

Police said they found a handgun and a long gun in the Theorets' house, but would not say whether they had evidence to show anyone was shot during the incident.

Investigators are waiting for autopsy results to determine the causes of death, police said.

Residents of Ryerson Township and the nearby village of Burk's Falls have expressed shock at the deaths, saying the area about 300 kilometres north of Toronto is typically a very quiet one.

Note to readers: This is a corrected story. An earlier version had an incorrect spelling of Raija Turunen's last name based on police information at the time.

News from © The Canadian Press, 2018