Jennifer Hudson's estranged brother-in-law, William Balfour, was arrested late Monday in the slayings of the Oscar winner's mother, brother and seven-year-old nephew, according to Chicago police and the Chicago Tribune.
Formal charges have not yet been brought by the Cook County prosecutor's office, but Balfour was transferred from an Illinois state prison – where he has been held on suspicion of a parole violation – back into police custody.
He has been considered the prime suspect for weeks.
Balfour, 27, who is married but separated from Hudson's sister, Julia, was arrested in the first-degree murders of Hudson's mother Darnell Donerson, 57, brother Jason Hudson, 29, and Julia's son - his own stepson - Julian King, 7.
William Balfour, who previously served prison time for attempted murder and car hijacking, was arrested hours after the first victims were discovered.
The bodies of Donerson and Hudson were found shot to death October 24 in the family home on Chicago's South Side by Hudson's sister, Julia.
The body of King, Julia's son, was found three days later in the backseat of Jason's abandoned Chevrolet Suburban. All died from gunshot wounds.
Balfour and Julia Hudson married on December 30, 2006.
They lived together at the family home at first, but their relationship was marred by myriad fights over money and infidelities, according to family members.That led to Balfour being thrown out of the house in recent months.
He had voiced threats against Julia and her family, sources say. His mother, Michele Balfour, told reporters her son had discussed divorce.
No motive for the slayings was disclosed, but police say on the morning of the killings, Julia Hudson reported to her job as a school bus driver and learned that her paycheck had been garnered due to unmade payments on a car that Balfour had taken earlier. She then called Balfour.
Sources told the Chicaago Tribune that William Balfour proceeded on to the Hudson home and fired through the front door, striking Jason Hudson, and Darnell Donerson was allegedly shot as she entered the living room.
Julian King was reported missing from the home after Julia Hudson came home about 3 p.m. and alerted police. The boy was the subject of a three-day search until his body was found inside a white SUV on October 27.
A bullet lodged in the vehicle suggests he was shot in the car.