Flames leaped from the second story of a house at 1911 S. Homan Avenue in Lawndale neighborhood on Chicago's West Side.
The blaze broke out at approximately 2:20 a.m and quickly spread to two neighboring homes.
Officials confirmed that the two people found dead inside the home were a sister and brother identified as Eva Pearson, 91, and 95-year-old Early B. Jiles.
"We had been trying to get them out of here, but they promised us Monday they would come and live with us," said Elzena Gilliam, goddaughter of one of the victims.
Gilliam also said the siblings had difficulty getting around. One was in a wheelchair, and the other used a walker.
Firefighters had a tough situation on their hands battling the blaze. When they arrived on the scene at, the home was enveloped in flames. The house was destroyed completely.
"We encountered bars, a steel door," said Dep. Dist. Chief William Monroe of the Chicago Fire Department "We found heavy smoke and fire upon arrival."
Crews actually returned to the scene later Sunday morning to put our hot spots that had ignited.
The two-alarm fire got so big that it spread to homes on both sides of it, 1909 and 1915 S. Homan, causing considerable damage to them as well.
"I was next door. I smelled smoke, ran upstairs, then ran to the back, then to the front. By that time, the flames were shooting out," said neighbor Robert Blunt.
Both of the neighboring homes were also occupied at the time, but it appears that other than a woman who was treated on the scene and then taken to the hospital as a precaution, there were no injuries there.
Investigators still do not know what caused the fire. It is unknown if there were working smoke detectors inside the home.
Firefighters said they would return to the West Lawndale neighborhood Sunday to hand out smoke detectors to residents, something the fire department always does when someone dies in a fire.