INDIANAPOLIS (WISH) — A Tuesday morning apartment fire on the city’s northeast side that injured a firefighter and displaced 15 people was intentionally set, the Indianapolis Fire Department said.

Crews from the Indianapolis and Lawrence fire departments were called around 2:45 a.m. to a car on fire in a carport on Cedarstone Court. That’s part of an apartment complex off of East 56th Street, just west of I-465.

Upon arrival, firefighters found a two-story apartment building and its attached carport engulfed in flames.

“Occupants of the main fire apartment told firefighters they awoke to see their car on fire and evacuated. They have no idea what could have caused the fire,” IFD Battalion Chief Rita Reith said in a release.

Firefighters helped one person out of the burning building, according to Reith. The other residents made it out before crews arrived.

A firefighter from Lawrence “sustained a slight injury” while battling the blaze and was transported to a local hospital for evaluation, Reith said. No one else was injured.

Damage to the apartment building was significant, and the three families that lived there — three adults and 12 children — were displaced. IFD and the Red Cross were working with apartment management to find temporary housing.

IFD investigators determined the fire was arson but did not say how the blaze began.