BRIDGEPORT - Fire officials are investigating a blaze that tore through the former Remington Arms Factory Sunday.

The fire broke out just after 12:30 p.m. on the factory's third and fourth floors. The fire was the second at the vacant building in three months.

Investigators say they don't know what sparked the flames this time.

"At this point, we have no idea what started the fire," says Assistant Chief John Currivan, of the Bridgeport Fire Department. "We don't know if it's squatter. There's no electricity, no fuel ? some kind of incinerator was put in the building to start the fire."

The January fire is believed to be a case of arson.

Fire rips through vacant Bridgeport factory