A K-9 unit was called in Thursday night to the scene of a Lexington duplex fire.
Firefighters said blood was found on a broken window at the building on Harris Court near Winburn Drive.
Investigators said they were trying to figure out where the blood came from and whether or not anyone was hurt.
Firefighters said crews did not find anyone inside the duplex.
At least two rooms were damaged in the fire.
Investigators are trying to figure out how the fire started.