Three people have been killed in an attack southwest of Sydney.
The bodies of two victims, and a critically injured man who later died, were found inside the home on Juliet Cl at Rosemeadow about 1.30am on Sunday.
WATCH THE VIDEO ABOVE: Three people killed in Rosemeadow attack.
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A woman in her 60s and a man in his 20s were found dead by NSW Police officers responding to reports of an assault.
A 64-year-old man was also found inside the home with critical head injuries.
He was treated by paramedics at the home, and taken to Liverpool Hospital fighting for life, but later died.
A man and a woman were found dead inside the Rosemeadow home, and a second man died of his injuries shortly after. Credit: 7NEWS
A young man was arrested outside the home about an hour after the bodies were found. Credit: 7NEWS
A homicide probe is ongoing and a young man has been arrested in relation to the deaths. Credit: 7NEWS
Police allege that the victims were all assaulted by a man known to them.
Authorities arrested a 32-year-old man who arrived at the home in a silver sedan about an hour after the bodies were found.
He was taken to Campbelltown Police Station, but no charges have yet been laid.
A murder investigation is ongoing, and a report will be prepared for the coroner.
Anyone with information is urged to contact Crime Stoppers.
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