Desperate pleas for the safe return of starlet Jennifer Hudson's seven-year-old nephew ended in despair on Monday when police found the boy's bullet-riddled body in an abandoned vehicle on Chicago's west side.

Julian King had not been seen since Hudson's sister discovered the bodies of their brother and mother shot to death in the family home on Friday afternoon.

While it is too soon to guess at a motive, police believe "it wasn't the case of a stranger-type homicide", superintendent Jody Weis told reporters.

Weis said he was "pretty optimistic" the evidence would lead them to the killer.

Police have not yet identified a suspect in the case but the boy's stepfather, William Balfour, is considered a "person of interest", Weis said.

Balfour, who was taken into custody for questioning on Friday, is being held on a parole violation but has not been charged.

Estranged from Hudson's older sister Julia, he has denied involvement in the murders or disappearance, law enforcement sources said.

Reward offered

The Oscar-winning star of 'Dreamgirls' used her website and MySpace page to post photos of the chubby cheeked boy and offer up a $100 000 reward for his return.

In one photo, a smiling Julian cuddles with his grandmother: "that's how close they were" Hudson wrote. Others show how "he loves his mom" or "does the fat kid dance" or is "not the size of an average seven-year old" but has "a baby face."

Hours after his body was discovered, Julian's photo and the reward were removed from Hudson's website and replaced with the simple note: "Thank you all for your prayers and calls. The support has been overwhelming and we thank you for being there for us through this tough time. Sincerely, The Hudson Family."

Hudson was the one to identify the boy, saying "yes that's him" when his face appeared on a wall-mounted video screen, said Sean Howard, a spokesperson for the medical examiner's office.

She entered the room with her head bowed but "remained strong for her family. It was very clear she was the leader", Howard said.

"She held hands with her family. It was obviously a very emotional moment."

"Shocking"

It was a shocking end to a horrific ordeal, said Hudson's cousin Rev. Krista Alston, a minister at the Pleasant Gift Baptist Church in Chicago.

"It's shocking. It's unreal. We had been praying that it would not come to this," Alston said. "We know it's a reality now, but it's still shocking."

Police believe Hudson's brother, Jason (29) was shot through the door of the family home on Chicago's south side. The shooter then entered the home and kept firing, hitting Hudson's mother Darnell Donerson (57) as she entered the room.

Hudson's older sister, Julia, discovered the bodies around 3pm on Friday but there was no sign of her son.

Julian was found in the back seat of his uncle's missing sports utility vehicle shortly after 7am on Monday, police said.

Shot multiple times

It was not immediately clear when he was killed but it appeared as though he was shot multiple times in the vehicle, law enforcement sources said.

An autopsy will be performed on Tuesday.

Balfour had split up with Julia Hudson and moved out of the home she shared with her mother and brother, friends and neighbors said.

The 27-year-old baker has convictions for attempted murder, vehicular hijacking and possession of a stolen motor vehicle, according to the Illinois Department of Corrections. He was released from prison in May 2006 and is still on probation.

Hudson, whose star turn in 'Dreamgirls' earned her an Academy Award for best supporting actress in 2007, was in Florida promoting her latest movie, 'The Secret Life of Bees', when she got word of the tragedy.

She has shunned the spotlight since rushing home to the Windy City.

The 27-year-old was riding high with a new movie and a number one hit on the Billboard R&B/hip-hop charts from her recently released self-titled debut album, until the family tragedy upended her life.

AFP