William Balfour was found guilty on all counts in the murder of Jennifer Hudson's family Friday.
The estranged husband of Hudson's sister, Julia Hudson, had been charged with three counts of first-degree murder in the Oct. 24, 2008 killings of her mother, 57-year-old Darnell Donerson, her 29-year-old brother, Jason Hudson, and 7-year-old nephew Julian King, ABC News reports.
Balfour, 31, was also found guilty of home invasion, residential burglary and possession of a stolen vehicle related to the 2008 slayings of the entertainer's family.
Singer and Oscar-winning actress Jennifer, 30, was in court Friday and reportedly cried when the verdict was read aloud.
Closing arguments were made Wednesday and Balfour's lawyer had argued in court that there was no forensic evidence to link his client to the killings.
Balfour allegedly got into a jealous rage when he saw balloons at Hudson's -- a gift he believed to be from Julia's new boyfriend. He then went into the home around 9 a.m. and shot and killed Darnell in the living room, and Jason in his bedroom. Prosecutors said he then drove off in Jason's SUV with Julia's son, Julian, in the car and shot the 7-year-old in the head. Julian's body was found in the abandoned vehicle three days later.
According to lead prosecutor James McKay, Balfour told Julia a day before the killings, "If you ever leave me, I'm going to kill you, but I'm going to kill your family first."
Balfour will be sentenced to life in prison without parole as mandated by Illinois law.