A 50-year-old man, a 49-year-old woman and two teenage boys were found dead at their home in the Perth suburb of Mosman Park on Friday.

A line of Western Australia Police vehicles, including an SUV, a van, and a utility truck, are parked along a residential street behind blue and white checkered police tape.

A homicide detective has told reporters that police were investigating the matter as a murder-suicide. Source: AAP / AB

Warning: This article contains distressing content.

A man, a woman and their teenage children have been found dead in their home in what police are treating as a double murder-suicide.

The 50-year-old man, a 49-year-old woman and two boys, aged 14 and 16, were found dead at their home in the Perth suburb of Mosman Park on Friday morning.

Three pets were also found dead at the home.

There was no weapon used in the incident and police had no record of family violence matters involving the family, homicide detective Jessica Securo said.

“Although this investigation is in its infancy, police are investigating this matter as a murder-suicide,” Securo told reporters.

“There is no ongoing risk to the community.”

Both children had experienced “significant health challenges”, and the family had previously engaged with care services, Securo said.

A cause of death is yet to be revealed, but a note was found at the home, she said.