A massive fire tore through a vacant Little Village neighborhood warehouse early Saturday on the Southwest Side.
Crews were called to the blaze in the 2500 block of South Kostner about 2 a.m., according to the Chicago Fire Department.
A fifth alarm was called within an hour, bringing 22 fire engines and about 170 firefighters to the scene. A rear wall of the three-story, block-long building collapsed, fire officials said.
Investigators think one or more homeless people trying to keep warm overnight might have accidentally ignited the fire, officials said.
The fire was put out by 8:43 a.m., according to fire officials. No injuries were reported.