The fire was reported about 11 o'clock Friday night. By the time firefighters arrived, investigators say they encountered heavy fire and smoke.
Action News has learned that the fire also damaged several vehicles parked inside the building, which has a garage. The fire reached two alarms before being contained.
The building is the former site of the New Jersey National Guard armory.
Invesigators have not pinpointed what caused the fire. They are labeling the fire suspicious. No injuries were reported.
