A Dayton fire crew on a medic run smelled smoke and found the house on North McGee Street burning from the basement to the second floor, District Chief Barry Baldwin said.
Crews searched the house and found no one and also two people leaving the scene. That prompted the call for the arson investigator.
"Somebody started it. There are no utilities to the property," Baldwin said. "It looks to us like it was obviously an arson."
Initial Report: Crews dispatched to North McGee Street on the report of a structure fire found at least two fires in the vacant house.
A Dayton Fire Department arson investigator has been requested to investigate the cause and origin of the fire, which was dispatched just before 11 p.m.