Authorities tentatively identified the body found Friday in a burning car in Godfrey.
However, police did not release the identity Saturday while they awaited further forensic evidence, said Madison County Sheriff's Office Captain T. Mike Dixon.
A neighbor reportedly heard a loud noise minutes after noon Friday and saw a vehicle on fire in a neighboring driveway.
Madison County Sheriff's deputies and the Godfrey Fire Department responded to the scene and put out the fire. A search of the interior of the vehicle revealed the remains of a single, deceased occupant.
Investigators with the Madison County Sheriff's Office, the Madison County Coroner's Office, the Illinois State Fire Marshal's Office and the Illinois State Police continue to investigate the fatal fire.
The cause of death still is being investigated, but no conclusive evidence suggested the death or fire is criminal in nature, Dixon said.