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.

Smoke and flames billow from a Little Village warehouse early Nov. 5, 2016. | Network Video Productions

Firefighters battle an extra-alarm warehouse fire in Little Village early Nov. 5, 2016. | Chicago Fire Department

All companies working. Vacant block long structure 26th & Kostner, Little Village neighborhood pic.twitter.com/UY4tdyxnlC
— Chicago Fire Media (@CFDMedia) November 5, 2016

Firefighters battle of massive warehouse fire in Little Village early Saturday. | Network Video Productions

Firefighters battle of massive warehouse fire in Little Village early Saturday. | Network Video Productions