Fire destroyed a campaign office of presidential candidate Hillary Rodham Clinton in western Indiana early Friday.
Two people were inside when the fire broke out but escaped without injuries, said Terre Haute Fire Department spokesman John Gardner.
Gardner said nothing so far had indicated the fire was arson.
"But we're doing a full investigation on it like any other commercial structure fire," he said.
Clinton's campaign had no immediate comment.
A volunteer firefighter driving past the building in a commercial district along U.S. 41 south of the city's downtown spotted flames on the roof shortly after midnight and warned those inside, Gardner said.
The roof of the one-story building partially collapsed and a part of the front wall collapsed on a parked car, which then caught on fire. The adjoining office of a staffing services agency had water and smoke damage, but a fire wall held back the flames, Gardner said.
Clinton is battling Illinois Sen. Barack Obama for the Democratic presidential nomination. Both candidates have set up offices throughout Indiana as they vie for the state's 72 delegates in the May 6 primary.
Former President Clinton spoke Thursday night in nearby Vincennes and had a campaign visit set for Friday in the small city of Clinton about 20 miles north of Terre Haute. Obama was expected in Terre Haute later Friday.