Two dead and one injured in domestic violence incident

Officers found a 64-year-old man suffering serious head injuries, along with the bodies of a woman in her 60s and a man in his 20s.

The bodies are yet to be formally identified.

Police say the victims "were assaulted by a man known to them".

NSW Ambulance paramedics treated the injured man at the scene and he remains in a critical condition.

An hour later, police arrested a 32-year-old man who arrived at the house in a silver sedan.

He was taken to Campbelltown Police Station.

Police have set up a crime scene and are preparing a report for the coroner.