The DuPage County coroner's office determined the deaths of Tom Lambert, 57, and Jan Lambert, 56, were accidental, according to the article. The fire started on the first floor toward the back of the home but investigators have not been able to determine the exact cause of the blaze, the Daily Herald reports.
Fire officials responded to the Lamberts' two-story home at 1212 Field Court around 6:50 a.m. Crews responded to the scene within three minutes, bringing a total of 13 emergency vehicles, seven chief officers as well as a heavy rescue squad, according to the fire department.
Neighboring residents were evacuated from their home due to the risk of a ruptured natural gas line, but they were not injured.
Within 10 minutes of arriving to the scene, "fire personnel were removed from the building due to concern of a possible structural collapse," according to the fire department.
Firefighters discovered the bodies once they were able to re-enter the home.
A 21-year-old caregiver living at the Lamberts' home, Allen Belaguas of Orland Park, was critically injured in the fire and the Daily Herald reports doctors have said his chances of recovery "are slim" while Tom Lambert's father and sister were able to escape the blaze with only minor injuries.