'U r killer': House vandalised after firebombing

A house in Sydney's west has been vandalised with the words 'U r killer' and 'U r murderer' after it was firebombed overnight.

Police were called to the home in Greenacre at about 3am after reports of the front of the property going up in flames.

Officers said the people inside were woken by the flames, which left the front door charred and windows smashed.

Both people inside were taken to hospital, one suffering minor burns.

The family owns a local business near the home.

Police are investigating the incident, and anyone with information should call Crime Stoppers on 1800 333 000.