A fire in a Columbia, Maryland, apartment building in the predawn hours of Tuesday has left 20 people without homes, and the police are looking into whether the fire was started on purpose.

The fire, on Hickory Ridge Road, started at about 3:30 a.m., the Howard County government said in a news release. It took 45 minutes to bring it under control.

One person suffered minor injuries while escaping; a firefighter also suffered minor injuries.

The police said they’ve found what “may be remnants of an incendiary device,” and are investigating the incident as possible arson.

The fire affected 12 apartments and caused about $500,000 of damage.