RELATED: Chicago fire leaves man dead, 2 siblings injured on South Side
The fire broke out about 6:05 a.m. in the basement of a home in the 5700-block of West 64th Street, CFD and Chicago police said.
A 60-year-old woman, who the Cook County Medical Examiner's Office identified as Susan M. Collopy, was found dead in a first-floor bedroom when fire crews arrived. A 63-year-old man was in good condition, a 34-year-old woman was in fair condition and a 7-year-old boy was in serious condition, officials said.
The three survivors, Collopy's husband, daughter and grandson, according to neighbors, had managed to get out of the building.
Neighbor Renaldo Vera said he was asleep when the fire began, but once he heard his dog barking he woke up to a lot of commotion.
"I heard people and heard the window break. I screamed out the window 'are you OK?' She said 'no,'" Vera said. "I ran downstairs and ran across to where they're at. The grandfather started breaking the windows; I started helping him out, getting the little boy out. Anybody would have done the same."
WATCH: Chicago fire official gives latest on fatal Clearing fire
It was a heroic act that is giving those three people a chance to live Monday morning, as they're treated at nearby hospitals.
"We see each other all the time when I'm out. We are very close in this community," Vera said.
Other neighbors are struggling to wrap their heads around what happened.
Jessica D. said the blaze claimed the life of her long-time friend, Sue.
"We have kids the same age. My daughter is one year older than her daughter is. We've been together for quite a few years, helping each other whenever it's needed," she said.
The two lived next to each other for the last 30 years, often competing on growing a better garden and making a lifetime of memories.
"I still don't believe that she's gone. I still don't believe she's gone," Jessica said.
The man and boy were taken to Loyola hospital and the woman was taken to Christ hospital, Chicago police said.
Chicago fire officials continued to investigate the cause of the blaze later Monday morning as smoke could still be seen coming from the building. There was visible damage to the home.
They said there were working smoke detectors in the home, but CFD still planned to pass out smoke alarms and safety information in the area at 10 a.m.