As of yet, there has been no confirmation on the identity of the body found in the white SUV Monday morning.
The Cook County Medical Examiner's office and Chicago Police Department sent officials to the scene of a white SUV on the city's West Side Monday.
When police issued an Amber Alert for Julian on Friday, they identified a 1994 white Chevrolet Suburban with Illinois license plate X584859 as connected to the case.
Julian King, 7, has been missing since Hudson's mother and brother were found dead in their home Friday.
Over the weekend, Oscar-winning actress Hudson offered a $100,000 reward for the safe return of her nephew.
"Thank you all for your prayers and your calls. Please keep praying for our family and that we get Julian King back home safely," Hudson said in a posting on her MySpace page Sunday.
"If anyone has any information about his whereabouts please contact the authorities immediately."
Julian was described as being 4-feet-11 and 130 pounds and was last seen wearing a striped brown polo shirt and khaki pants, according to an Amber Alert released by police.
Hudson's mother Darnell Donerson, 57, and her older brother, Jason Hudson, 29, were murdered in Chicago on Friday afternoon.
Police confirm they have taken a person into custody but are not saying who.
News reports, however, say that person is Hudson's brother-in-law, William Balfour. According to the Department of Corrections, Balfour, 27, is on parole. He spent nearly seven years in prison for attempted murder, car hijacking and possessing a stolen vehicle.
Hudson won an Academy Award in 2007 for her role in "Dreamgirls" and was a contestant on "American Idols."