"This victim did suffer multiple gunshot wounds to the back and front of the body," said crisis responder Andrew Holmes.
The fire started around 3 p.m., according to officials as flames tore through the house in the 5900-block of South Sangamon Street.
Investigators put the blaze out and then found the body.
"State marshal is out here with the dogs on the inside, so they are trying to determine if this person was shot on the inside. If he was shot on the inside then there may be some shell casings on the inside, so that could tell us a whole lot," said Holmes.
Neighbors said the home has been vacant for quite some time. Now, police want to know who was at the home before the fire and how long the unidentified man had been there as investigators work to figure out how the fire started.
"They trying to cover up a homicide, so it is definitely arson," Holmes added.