Chicago police say the FBI has joined them in the hunt for Jennifer Hudson's missing nephew in the wake of the [article id="1597912"]double-homicide of Hudson's mother and brother[/article]. At a press conference on Saturday evening (October 25), Hudson's sister Julia pleaded for the return of her 7-year-old son, Julian King.

During the conference at Pleasant Gift Missionary Baptist Church, Julia Hudson and the boy's father, Greg King, asked the public for help in finding Julian, who sometimes goes by the nicknames "Juice Box" or "Dr. King."

"All I ask, I don't care who you are, just let my baby go," Julia said. "I just want my son back. He doesn't deserve this."

Julia said that when she told Jennifer the news, the singer/actress "was screaming" and "flew in right away."

"It hurts," Julia told reporters. "We're in a state of shock. I don't know what else to do but pray. He's out there. Just let him go."

Chicago Mayor Richard Daley offered his condolences to the Hudson family in a separate press conference, saying, "Our prayers go out to [them], and [the police] are working to make sure they get the offender and other facts involved in the case about her nephew."

Chicago Police Superintendent Jody Weis told reporters that the homicides "appear to be some type of domestic situation, but that's very preliminary."

Police said they had responded to a call shortly before 3 p.m. Friday at a South Side residence belonging to Hudson's mother, Darnell Hudson Donerson, where they found both Donerson and Hudson's older brother, Jason, who had been shot and killed. Donerson was 57 years old; Jason was 29. King was declared missing in the aftermath of the shooting.

Hudson's brother-in-law, [article id="1597920"]William Balfour, was identified as a suspect and arrested late Friday[/article], but the boy remained missing. Police told MTV News that Balfour is not the only person being questioned and they're talking to "a lot of people."

Hudson traveled from Tampa, Florida, to Chicago late Friday, and went to the medical examiner's office with other members of her family to identify the bodies of her mother and brother. The medical examiner's office said that both victims had multiple gunshot wounds, and some defensive wounds as well.

Balfour's mother, Michele Davis Balfour, has insisted to reporters that her son is innocent. "Out of no means did my son do this," she said. "And I'm very upset with the police, because they are refusing to let me see my son. I didn't raise no murderer. He was not a child abductor. They have the wrong person."

Balfour and Julia Hudson had been married for about a year-and-a-half, but had recently separated, Balfour's mother told reporters. Public records show that Balfour named the Hudson home as a residence up through October, but he had recently started listing another address as his residence.

Though the couple also shared vehicle registration, a dispute seems to have arisen over the possibly unauthorized sale of one of Julia's cars, according to a post on her MySpace page.

"We just have to follow the evidence," Weis told reporters, "and right now, that's what we're doing, and we will follow it to wherever it leads. ... We'll work closely with the family, we'll develop leads, and we'll pursue them to a logical fruition."

Community activist Ziff Sistrunk told the Chicago Tribune that he was looking for a hundred volunteers to form a search posse, telling the paper, "We need to find this kid."