There were reports of a family living in the home at 73rd and Vincennes. Investigators spent much of the day Tuesday using heavy machinery to dig through the rubble looking for any evidence. So far, no victims have been found.
"This is a suspicious fire and, again, we weren't able to conduct a full search of the entire structure and we were able to find gas cans in a couple of locations," Deputy District Chief Dan Cunningham, of the Chicago Fire Department, said.
"I live over there. I was in the back of my house and the whole building and the whole ground shook like, 'boom!' And it was an explosion," Cheryl Brown, neighbor, said.
A CTA bus driver told firefighters he heard an explosion and then saw the four-unit apartment building catch fire around 1 a.m. Tuesday. Part of the structure collapsed, making it unsafe for firefighters to conduct a thorough search of the building.
"It is way too dangerous. Part of the building that the neighbors say the family was living in is totally collapsed. So, there will be no entry into that building by our personnel," said Deputy Chief James Mungovan of the Chicago Fire Department.
A family recently moved out, neighbors said. Investigators say accelerants were found at the scene, but they have not determined the exact cause.