A 29-year-old man has been arrested in connection with the deaths of a 39-year-old Ajax mother, her 15-year-old son and her 13-year-old daughter.

Durham Regional Police officers were first called to the home on Hilling Drive, near Lake Driveway West, at around 11 a.m. Wednesday after a friend of the woman attended the residence to check on her wellbeing but was “refused entry” by a man at the residence.

That man then fled the scene in a black vehicle. Police confirmed at around 7 p.m. that the suspect had been arrested in Oshawa.

As of Wednesday evening, he had been charged with two counts of second-degree murder and one count of attempted murder. Speaking at the scene at around 9 p.m., Const. George Tudos told reporters the suspect’s name will not be released until the case is before the courts on Thursday.

Tudos said officers responded to what was classified as “unknown trouble” at the home. There, they discovered the bodies of two people and located a teenaged girl suffering from serious injuries.

The third person, identified as a 13-year-old girl, was also transported to hospital from the scene but was later redirected to a Toronto-area trauma centre where she later succumbed to her injuries at around 10 p.m.

Police confirmed that the deceased are a mother and son and that the girl in hospital is her daughter.

CTV News Toronto has learned that the victims are Krissy Pejcinovski and her son, Roy Pejcinovski.

“Right now, this is a homicide investigation,” Tudos said. “We have two deceased parties. We have an outstanding suspect. It’s still an ongoing investigation with further information to follow.”

Police said the man seen at the residence earlier in the day is believed to have been in a relationship with the female victim.

The car he drove this morning was found abandoned in a plaza near Brock Road and Highway 401 in Pickering earlier this afternoon.

“The vehicle was unoccupied,” Tudos said. “We know this was the same vehicle police were initially looking for, the vehicle that the suspect left in.”

He said the deaths are an “isolated incident” but “not a random attack.”

“If there was a risk to public safety, we would definitely put that information out or advise the public of any dangers,” he said. “Right now we believe this is an isolated incident. We hope the public and the community has faith that our investigators will do their job and try to find the person responsible for these two deaths.”

Officers remain in the neighbourhood canvassing and speaking with witnesses.

“We’re in the process of interviewing some witnesses that were here at the scene prior to police arriving and hopefully once we speak with them, we’ll have a better understanding of who we’re looking for and exactly what transpired in that residence,” he said.

Meanwhile, a portion of Hilling Drive remains roped off to accommodate the police investigation.

A neighbour was one of the first people on the scene.

“We came home for lunch and there were a few cop cars – none of this was roped off yet – there were just a few cop cars and a couple ambulances," the woman, who did not provide her name, said. "That’s all I really know. They’re not telling us anything."

Neighbours say the family has been in the neighbourhood for "a couple years."

“The young boy was into hockey and the two girls, they’d pass by and say hello,” said Alex Kervick, who lives next-door to the family. “The same with the mother, Krissy, she’d pass by and say hello… and that was it.”

Dawson Jordan, a friend of the family, told CTV News Toronto that at least one of the teenaged daughters was not at the home at the time of the murders.

She was said to be in Driver’s Ed and was pulled out of class by police.

The accused is scheduled for a bail hearing on Thursday.