The façade and front door of a residence in Mqabba were damaged in an arson attack early yesterday morning, the police said.
A curtain and the door behind it were daubed with an inflammable liquid before being set on fire.
Someone reported the door ablaze in Triq il-Madonna tal-Ġilju at about 6 a.m. but the fire was put out before the police arrived.
The occupants of the house, who were inside at the time, were not injured.
Magistrate Michael Mallia is holding an inquiry.