Officials are investigating a fire in Germantown that occurred early Sunday morning.

One of the residents of the house on the unit block of East Coulter Street told ABC News that he awoke to a loud bang around 1 a.m. and ran downstairs to find the living room engulfed in flames.

He said the house also had its windows broken by an unknown suspect a month ago. "They busted my windows out," he said, "and a month later we get this firebomb."

Three adults and a four-month-old infant were rescued, Deputy Chief Harry Bannan said at the scene.

He said fire officials had been to the property next door "at least 10 times," including for "two incendiary fires." He said he did not know if Sunday's fire was connected to the earlier fires next door.

A fire department spokesman told The Inquirer that the fire marshal is investigating.

- Justine McDaniel