The deaths of four adults found in an east-end Toronto home on Wednesday were the result of a murder-suicide, according to police.

The police investigation into the bodies of four adults found in an east-end Toronto home has confirmed the deaths two males and two females were the result of a triple homicide that was followed by a suicide, Det. Sgt. Pauline Gray told a press conference in Toronto on Thursday. (CBC)

Two males and two females died as a result of a triple homicide that was followed by a suicide, Toronto Police Det. Sgt. Pauline Gray said at a press conference Thursday. A family dog was also found dead at the home on Welwyn Avenue.

Police are not confirming the names of the victims nor the causes of their deaths, saying only that the incident appears to be a "case of familial violence."

Neighbours have identified the couple living in the home as Keith and Wanda Delong, believed to be in their late 50s or early 60s.

The retired couple had two grown children — a son in his 30s named Richard who lived with the couple as he dealt with a prolonged illness and a daughter, Elizabeth Tompkins, who had reportedly arrived Tuesday night for a visit, neighbours said.

Police sources reportedly told the Toronto Star Thursday that autopsies, expected to be conducted Saturday, will indicate the father killed his family before taking his own life.

While police haven't publicly indicated who may have been responsible for the homicides, Gray said Thursday investigators aren't looking for a suspect and are confident the individual who committed the homicides also died in the home.

"Any public safety concerns should at this point be alleviated, and I ask that you allow this family to grieve with dignity and grace," she said.

Neighbours identified Keith Delong as one of the residents of the Toronto home where four people were found dead Wednesday morning. (CBC)

A man who called in the incident to police was initially arrested near the scene, but has since been released after it became apparent he was not involved in the homicides. No charges were laid against the man, who neighbours identified as Tompkins' husband.

"The officers had reasonable grounds to believe that the reporting male had involvement in the death of the adults," Gray said.

"As the case unfolded and more forensic evidence was uncovered, it became apparent that the tragic deaths of the family was, in fact, a triple homicide-suicide.

'Do not enter, call police'

Police received a call around 8:20 a.m. Wednesday regarding a suspicious incident in the residential area east of Markham Road. Along with the bodies, police discovered a note taped to the front door of the house that read: "Do not enter, call police."

Some neighbours told CBC News there were no signs of trouble among family members, who were described as "lovely" people, but the Delongs had reportedly remortgaged the house they bought 34 years ago in September.

The family was also struggling to care for their terminally ill son, a friend of the Delongs said Thursday.

"I think they tried everything — accupuncture, and he'd had different operations and gone to different specialists and still the pain was there," Janet Brooks told CBC News.

Wanda Delong, wife of Keith, is also said to have lived at the home on Welwyn Avenue. (CBC)

She said the news of deaths was utterly shocking and "the most bizarre thing I've ever come across."

Keith Delong was said to be a gun collector and an avid sportsman who rarely showed signs of stress.

"He wasn't the type to blow his anger 'cause we've never, ever heard any angry voices from that house, ever, for as long as we've been here, which is 22 years," a neighbour said.

Police said reports that Keith was a gun owner may not be relevant to the case.

"Many people own guns and they're not used to wipe out other family members," said Staff Insp. Brian Raybould.

Investigators are still in the home collecting forensic evidence. No further details on the deaths will be released until the autopsies are conducted and the next of kin, many of whom live outside of Canada, are notified, Gray said.

Whitby house also sealed off by police

The Delongs were scheduled to depart for Mexico on Wednesday to reportedly aid a gravely ill family member.

Along with the home on Welwyn Avenue, police have also sealed off a house in Whitby, Ont., belonging to Tompkins and her husband.

The husband, who was held in police custody for nearly 15 hours, apparently went to the Delong's home Wednesday morning after no one answered the phone there, his sister told reporters Wednesday from the police station.

Tompkins' husband found the note on the front door of the house, she said, when he went to check on his wife, who had apparently gone to her parents' house Tuesday evening after receiving news there was a "big problem" with her grandmother.

The man who was arrested at the scene was already facing a family tragedy when he discovered the murder-suicide, the sister said. Their family learned Wednesday that an elder brother, who is in hospital with colon cancer, has one week to live, she said.

With files from the Canadian Press