Belleville Police and St. Clair County coroner's investigators late Tuesday morning were at a house in the first block of North 16th Street in Belleville.
Investigators said there were human remains that had been in the home for some time. There was no immediate indication as to the cause of death.
The house was closed up and there were no air-conditioning units apparent. Investigators said it was too soon to speculate about the recent heat having a role.
Investigators also placed an evidence marker next to a hypodermic syringe found outside the house.
Eight investigators and Police Chief Bill Clay were at the house by the time the body was removed at 1:53 p.m. Tuesday.