Body found in Hudson nephew hunt

US police hunting for actress Jennifer Hudson's missing seven-year-old nephew say they have found the body of a boy in a white car.

Julian King has not been seen since Hudson's mother and brother were found shot dead in their Chicago home.

Police issued a search alert for Julian and a 1994 white Chevrolet Suburban vehicle after Friday's discovery.

There is no confirmation of the body's identity. Hudson has offered a $100,000 reward for her nephew's safe return.

A spokesman for the Cook County Medical Examiner's office told the Associated Press that investigators had been sent to the scene.

Vehicle match

Aerial news footage showed the vehicle being photographed by police and then towed from West Side, Chicago.

It was towed with the body still inside, AP reported.

Police later said the licence plate number matched the number listed in an earlier police alert issued about the boy's disappearance.

Earlier, Chicago police spokeswoman Monique Bond said detectives were working around the clock on the case.

"There's a lot of forensic evidence. We have to work the evidence and try and solve this case. Most importantly, we want to find the child," she said.

Stepfather's arrest

Julian's mother Julia, Jennifer Hudson's sister, found the bodies of Darnell Donerson, 57, and Jason Hudson, 29, at the family home.

Julia's husband, William Balfour - the boy's stepfather - has been arrested. No charges have been laid.

He was transferred from police custody on Sunday to the Illinois Department of Corrections "based on his active parole violation unrelated to this investigation," a corrections spokeswoman told AP.

Jennifer Hudson, 27, a singer-turned-actress who found fame on American Idol in 2005, won an Oscar for best supporting actress in the hit film Dreamgirls in 2006 and starred in the film Sex and the City.

She is currently starring in The Secret Life of Bees while her song Spotlight is No 1 in the Billboard R&B charts.