The medical examiner positively identified the body found in the Chevrolet Suburban as Julian King, Monday afternoon.
Earlier Monday Deputy Chief Cmdr. Wayne Gulliford said police had responding to "a call about a suspicious auto" in the west side of Chicago at approximately 7 a.m. when they found the body inside a parked white Chevy Suburban, which had a license plate matching the description in the child's Amber Alert.
He had no details on the body, pending the medical examiner's report.
Julian has been missing since Hudson's mother and brother were found dead in their home Friday.
Over the weekend, Hudson offered a $100,000 reward for the safe return of her nephew.