The Federal Bureau of Investigation joined police officials on Saturday in an attempt to find the missing 7-year-old nephew of Academy Award-winning actress Jennifer Hudson, whose mother and brother were found dead a day earlier in her childhood home.

Julian King has been gone since Friday, when the slayings took place, and authorities suspect that his stepfather, William Balfour, is the mastermind behind his disappearance.

After an Amber Alert has been issued in the United States and Canada for the little boy, his mother, Julia Hudson, and his dad, Greg King, attended a news conference so as to beg the person or people who had captured their son to release him.

“Let my baby go,” the “Dreamgirls” star’s sister told reporters, as there was still no word from her child or his kidnappers.

The boy was at his grandmother’s place when he disappeared. Darnell Hudson Donerson, the actress’ mother, and her 29-year-old son, Jason Hudson, were found dead on Friday afternoon. Darnell Donerson, 57, was found shot in the head in the living room, while Jennifer Hudson’s brother, who was shot to death in the chest, was discovered in a bedroom. According to police, experts detected defensive injuries on one of the victims, a fact that suggests at least one of the killings was generated by domestic violence. In addition, the murderer or murderers did not break into the house, as no signs of forced entry were indicated.

Chicago police spokesman Daniel O’Brien explained that the FBI was asked to help in the search of the boy, as Julian King might have been taken across state lines. Daniel O’Brien refused to confirm information in numerous media reports regarding the arrest of 27-year-old William Balfour, Reuters reported.

In keeping with reports, Balfour, who was involved in a relationship with Julia Hudson, was taken into custody as a suspect in the double murder investigation.

Moreover, William Balfour is far from being law’s best friend. Up to now, the man has been sentenced for attempted murder, car theft, as well as vehicular hijacking, and was released from prison approximately 2 years ago, according to records on the Illinois Department of Corrections’ Web site.

Although Daniel O’Brien said that several people had been interrogated with regard to the slayings, he added that no one had been charged with the homicides. He did not disclose the identities of the suspects, but all eyes are on William Balfour, as police spokeswoman Monique Bond said on Friday that the murders seemed “to be domestic related.”

William Balfour’s mother, Michele, informed the Chicago Tribune that her son had been married to Julia Hudson for a few years, but they were estranged when the unfortunate event occurred, as Darnell Donerson had forced him to leave her home last winter.

Update: On Sunday, Jennifer Hudson offered a reward of $100,000 for information about her nephew who went missing from the murder scene,

Hudson has issued a cry for help at the Internet network Myspace Her message included a photo of the missing boy, who is the son of Hudson's sister, Julia.

Hudson sang the American national anthem at the Democratic presidential nominating convention in Denver, Colorado, in August. Democratic nominee Barack Obama and wife Michelle have sent her condolences.