The Oscar-winning actress and singer has often credited her rise to fame to her upbringing in the impoverished neighborhood on Chicago's South Side where she went to grade school and sang in church.
At that church, her sister pleaded for the safe return of her 7-year-old son, Julian, on Saturday, a day after the siblings' mother and brother were found shot to death at the family home in the Englewood neighborhood.
"I don't care who you are, just let the baby go," Julia Hudson said to a crowd from the podium of the Pleasant Gift Missionary Baptist Church with the boy's father, Greg King, at her side.
"I know he's out there," she pleaded. "Just let him go. Put him on the side of the street. He'll sit there. Somebody will see him. He'll probably cry until somebody comes along."
Authorities were holding a suspect with ties to the family, but no one had been charged Saturday. Law enforcement sources told the Chicago Tribune and Chicago Sun-Times that William Balfour was in custody, and the man's mother said he is Julia Hudson's estranged husband.
Julia Hudson did not address her relationship to Balfour, who was named in an Amber Alert issued after Julian's disappearance. An alert remained in effect Saturday warning people to be on the lookout for Julian, possibly in a white Chevy Suburban.
Julia Hudson noted that her brother's white truck was missing, but authorities did not say if it was the same vehicle mentioned in the Amber Alert or whether they were seeking additional suspects.
"My greatest fear has already happened," Julia Hudson said. "My greatest hope is finding my child."
Anyone with information is being asked to call 911 or the Chicago Police Department at (312) 747-8380.
Paul Ciliano, a former Chicago police officer and CBS News consultant, said the Englewood neighborhood where the crimes were committed is "probably the toughest neighborhood in the city of Chicago.
"This is notoriously violent area, the most shootings and car hijackings and tough-and-rumble place on the South Side of Chicago," he told Early Show anchor Priya David.
Ciliano said the first priority of the police right now is locating the missing boy. "That's their focus. They have the suspect, the number one suspect (and only suspect as far as I know) in custody, so right now all their efforts are going towards finding and locating this child and getting him home safely."
He said police are likely questioning Balfour's acquaintances. "I'm sure they have gotten his cell phone and know everybody he has talked to or texted the last 28 to 48 hours."
An autopsy Saturday showed Darnell Donerson, 57, and Jason Hudson, 29, died of gunshot wounds, according to the Cook County medical examiner's office. Their deaths were ruled homicides.
Police said a family member entering Donerson's South Side home Friday found a woman's body on the living room floor. Officers later found Hudson shot in the bedroom. At least one of the victims suffered defensive wounds, said authorities, who described the shooting as domestic violence.
That same day, Julia Hudson reported Julian King missing. Chicago police spokeswoman Monique Bond, who declined to comment Saturday on a suspect, said no one had been charged. She has said that investigators were talking to "a number of people in custody."
Bond said the FBI had been called to help in the search for the boy on "the possibility or any theory that he could have been take across state lines." But she added, "We have nothing to prove that."
Records from the Illinois Department of Corrections show Balfour, 27, is on parole and spent nearly seven years in prison for attempted murder, vehicular hijacking and possessing a stolen vehicle. Public records show one of Balfour's addresses as the home where Donerson and Jason Hudson were shot.
Balfour's mother, Michele Balfour, said that her son had been married to Julia Hudson for several years, but that they were separated. She also said Donerson had ordered him to move out of the home last winter.
Michele Balfour told reporters that she offered her condolences to the family and denied her son had any involvement.
"All I want is for my son to come home," she said.
Julia Hudson, 31, asked that the public look for her son, saying he answers to the nicknames Juice Box and Dr. King. She added that her famous sister was in Chicago on Saturday, a day after she called her in hysterics.
Jennifer Hudson's fiance, who answered the phone, couldn't understand Julia Hudson and handed the phone to Jennifer.
"Despite her being who she is, she is still my sister," Julia Hudson said. "She understood what I was saying. She was screaming.
"She flew in right away, and we've been together since. We're all still in a state of shock. I don't know nothing else to do but pray."
The Hudsons, who have insisted on not allowing 27-year-old Jennifer's fame to alter their lives, lived in a three-story white house bookended by vacant lots. A grill and bottle of mustard stood on the lawn on Saturday, remnants of the barbecues they were known to throw on birthdays and holidays.
"They wouldn't turn anyone away," said Bob Israel, who lives in the neighborhood. "They didn't want to change a bit."
Hudson, who won an Academy Award for best supporting actress in 2007 for her role in "Dreamgirls," talked of the influence of her family often. In a recent Associated Press interview she said her family helped keep her grounded because her fame hasn't changed them.
"My faith in God and my family, they're very realistic and very normal, they're not into the whole limelight kind of thing, so when I go home to Chicago that's just another place that's home," she said. "I stand in line with everybody else, or, when I go home to my mom I'm just Jennifer."
Neighbors, including Dana Thomson, whose daughter worked at Burger King with Jennifer and Julia Hudson, echoed the sentiment.
"The mother didn't want to move. She was not accustomed to it," Thomson said. "She knew everybody here."
The tragedy comes as Jennifer Hudson's star continues to rise. Her song "Spotlight" is No. 1 on Billboard's Hot R&B/Hip-Hop charts and her recent self-titled debut album is selling well. She was featured in this year's blockbuster "Sex and the City" movie and also stars in the hit film "The Secret Life of Bees."