The dead included two young brothers - a 3-year-old and a 3-day-old baby.
The voices of people hoping to save the lives of those trapped in the house can be heard on the tapes.
No one inside the burning building made a call for help.
"The building at 3034 S. 48th Court is on fire," the caller told 911 emergency workers.
The first 911 call came from someone outside the apartment building, a woman arriving to visit her mother at 6:28 a.m. on Sunday, February 14. Firefighters say she may have saved many lives because many were asleep inside.
Investigators say they received 911 calls from several people, and firefighters were on the scene within minutes. But even by then, the fire was raging out of control when they arrived.
Investigators with the state fire marshal's office returned to the scene Wednesday morning, still searching for a cause.
The fire started in the back patio and traveled up to the attic where five of the victims were.
Allison Gist lost three children and two grandchildren who were sleeping in the attic. She blames the landlord for having only one exit, a back staircase, which was cut off by flames.
"I want him to pay for everything that he took away from me. He took my children away because of the unsafety of the building," said Gist.
Michael Ballard says he lived in the building for several years and considers his parents to be very lucky. He says they used to sleep up in the attic.
"We knew the guy who owned the building. He went to my parents' wedding. And, long story short, I know there are other things going on with him and his buildings that are not up to date, up to code," said Ballard.
Investigators are looking at many code violations including whether the detached garage Gary and Ginette Konrad have been living in was illegal. Now, the couple is staying in a Cicero hotel. They say everything they owned was destroyed and finding shelter with two dogs has been impossible.
"To get shelter, we have to give up the dogs, and then get shelter ourselves. So they can get adopted out by somebody else. So we had to give them up completely. We've lost everything else. Why would we want to give them up too," said Ginette Konrad.
The Konrads say they don't know where they will go now since their help from the Red Cross ends Thursday.
The cause of the fire has not yet been determined. There was a report that gasoline had been smelled at the scene of the fire by a worker. But at a news conference Wednesday, officials discounted that report and said that they have no evidence that gasoline or any accelerant was used. On the other hand, they have not ruled out arson.