Police say that 29-year-old Nathaniel Beller set the fire early Saturday morning. He died from injuries related to the fire.
His 4-year-old child also died after the home was set on fire. A 9-year-old child is still in critical condition.
The children's mother, Taniya Johnson, was killed in the blaze.
New details in the investigation reveal that Beller was released without charges three months before the incident- after he filled his bathtub with gasoline and threatened to burn his children.
According to the Chicago Sun-Times, Beller was freed after a psychiatric evaluation at that time.
Investigators said Beller hadn't been charged before he died.
Two middle-aged and elderly women were also hospitalized in fair-to-serious condition.