Western Australia Police are investigating a suspected murder-suicide after four people were found dead inside a home in the affluent suburb of Mosman Park on Friday morning, 30 January 2026. 

Emergency services were called to a residence on Mott Close at about 8.15 am after a family member attended the home for a pre-arranged visit and raised the alarm, Detective Acting Inspector Jessica Securo said, according to ABC News report. 

Police entered the property and located four deceased individuals believed to be part of the same family unit. The victims included a 50-year-old man, a 49-year-old woman, and two boys aged 14 and 16, all found inside the home, ABC News reported. 

In addition to the family members, three pets, two dogs and a cat, were also found dead, authorities reported. Detectives said there were no visible signs of violence and that no weapon was used in the incident, adding that police are unable to disclose the precise cause of death while the investigation continues. 

Detective Acting Inspector Securo described the scene as a “devastating tragedy” and said the family had no known history of family violence matters with police, as reported by ABC News. She also noted that both children had experienced significant health challenges and that the family had worked with support services prior to the incident. 

A note was found at the property, which police are examining as part of their inquiry, but investigators have not disclosed its contents. Police also said it is not known exactly when the deaths occurred, and part of the ongoing investigation is to determine the timeframe. 

Dozens of police officers, detectives and forensic personnel have been at the scene throughout Friday, with several nearby streets cordoned off while searches continue. Authorities say there is no ongoing threat to the community and have urged residents to stay away from the area while work is underway. 

Neighbours told the ABC they heard emergency services arrive around 9 am, and that the incident was out of character for the quiet, residential street. Police officers at the scene were reported to be deeply affected by the discovery and were provided with support. 

Western Australia Police are continuing to investigate the full circumstances surrounding the incident as part of a thorough forensic and criminal inquiry.