Excerpts from abc7chicago.com:

A fire that started just after 11:30 p.m. inside of a vacant 2 1/2-story home at 820 North Lawndale Avenue in Chicago destroyed that home and damaged two others in a 2-alarm fire. The vacant home collapsed during the fire. One firefighter was taken to a hospital with a minor injury and at least four people are trying to figure out where to go next as their homes are boarded up.

The cause of the fire is under investigation, but a neighbor saw two men in the backyard overnight lighting a bonfire.

From the Chicago FD Media on Twitter:

Update for the Still and Box at 820 N Lawndale- has been upgraded to a 2-11 Alarm.

Update- 2-11 Alarm at 820 N Lawndale has been struck out. 4 displacements red cross and human services enroute. 1 Firefighter transported from the 2-11 Alarm for minor injury. No other injuries.

2-11 Alarm fire in Chicago

CFD media photo

house collapses after a fire

CFD media photo