A group led by community activist Andrew Holmes right, pray at a makeshift memorial outside the home belonging to the family of Oscar-winning actress Jennifer Hudson in Chicago, Sunday, Oct. 26, 2008. Hudson's mother Darnell Donerson and brother Jason Hudson were found dead.[Agencies]

Jennifer Hudson's mother and brother have been shot dead.

The Oscar-winning actress' two family members - mother Darnell Donerson, 57, and 29-year-old sibling Jason Hudson - were brutally slain on Friday in their Chicago home. Their bodies were discovered by Jennifer's sister Julia Hudson.

The "Dreamgirls" star's representative Lisa Kasteler said: "We can confirm that there is an ongoing investigation concerning the deaths of Jennifer Hudson's mother, Darnell Donerson, and her brother, Jason Hudson. No further comment will be made and the family has asked that their privacy be respected at this difficult time."

Upon hearing the tragic news 27-year-old Jennifer, who was reported to have started "screaming", immediately flew to Chicago from Tampa, Florida.

Police are also searching for Jennifer's nephew, Julia's seven-year-old son Julian King, who had been staying at his grandmother's house in the city's South Side district and is currently missing.

Jennifer's brother-in-law William Balfour - Julia's estranged husband - is currently in custody and is being questioned about the double-murder and the boy's disappearance.

At the time of writing, police had confirmed 27-year-old William, who served seven years in prison for attempted murder and carjacking in 1999, is a suspect for the killings but is yet to be charged.

He was arrested just a few hours after the bodies were found - Darnell in the living room with a gun shot to her head and Jason, who had been blasted in the chest, in a bedroom.

Julia has issued an emotional plea for the return of her son.

She said: "I don't care who you are, just let the baby go. I just want my son. He doesn't deserve this. I don't know what else to do but pray."

Police have revealed they are talking to several other people in connection to the incident.

Jennifer Hudson and her family offered a $100,000 reward Sunday for the safe return of her missing nephew, as investigators looked for forensic evidence near the home where her mother and brother were found shot to death.

Mourners dressed in their Sunday best milled outside the childhood home of the singer and Oscar-winning actress, along with investigators seeking clues to the whereabouts of 7-year-old Julian King, the son of Jennifer Hudson's sister, Julia.

In a statement Sunday evening from publicist Lisa Kasteler, Jennifer Hudson appealed to the public for its help, offering the reward and asking that any information be given to Chicago police.

"Jennifer and her family appreciate the enormous amount of love, support and prayers they have received while she and her family try to cope with this tragedy and continue the search for Julian," the statement said.

Chicago police ramped up search efforts for Julian around the Englewood neighborhood, where Hudson grew up, and transferred custody of a "person of interest" in the killings to state authorities.

An Amber Alert remained in effect Sunday for Julian, who disappeared Friday, the day the bodies of his grandmother, Darnell Donerson, 57, and 29-year-old uncle Jason Hudson were found in the home they shared on the city's South Side. The deaths were ruled homicides.