
Police believe Julian was killed inside the SUV the same day as the adults, but "the exact timing" has not been determined, Peterson said.
Police have said far less than Illinois Prison Review Board Chairman Jorge Montes, who told reporters last month that Balfour's girlfriend or ex-girlfriend told police she saw Balfour with a gun "identical" to the weapon police recovered near the SUV where the boy's body was found — which they have said was the murder weapon.
When asked about the woman Tuesday, Peterson said that she cooperated with police, but would not say what information she provided, if any. Nor would he say that detectives have linked the weapon to Balfour.
Jennifer Hudson's publicist Lisa Kasteler declined to comment after Balfour's arrest on Monday, but Peterson said the family was "relieved and happy that the Chicago Police Department would bring this case to a successful conclusion."
Jennifer Hudson was a finalist in the 2004 season of "American Idol" and won her Oscar in 2007 for her film debut, a supporting role in "Dreamgirls." She has mostly stayed out of the spotlight and close to her family since the killings.
Detectives went to Stateville Correctional Center Monday afternoon, served an arrest warrant on Balfour and brought him back to Chicago.
Balfour had been in custody since the day the adults' bodies were discovered. After 48 hours — the longest Chicago police can hold a person without charges — he was taken by the Illinois Department of Corrections on a suspected parole violation. Balfour had served seven years for a 1999 attempted murder and vehicular hijacking conviction.
Balfour is scheduled to appear in bond court Wednesday afternoon. After the hearing, Cook County State's Attorney Anita Alvarez will talk about the case, her office said Tuesday.
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