A US jury has convicted a man of murdering three members of actress Jennifer Hudson's family in 2008. William Balfour, Ms Hudson's former brother-in-law, was found guilty on three counts of first-degree murder by the jury in Chicago. Prosecutors said Balfour shot Ms Hudson's mother, brother and seven-year-old nephew after his estranged wife refused to reconcile with him. Jennifer Hudson was overcome with tears as the verdict was read. The Oscar-winning actress was the first witness called in the trial and had attended every day of testimony. After the verdict, Ms Hudson and her sister, Julia Hudson - who was estranged from husband William Balfour at the time of the murders and later divorced him - released a statement saying "we have all suffered terrible loss in this tragedy". "It is our prayer that the Lord will forgive Mr Balfour of these heinous acts and bring his heart into repentance someday," they said in the statement. They also thanked prosecutors for their "dedication and tireless work" and praised police and trial witnesses. Circumstantial evidence The jury deliberated for three days before delivering its verdict. Balfour, 31, now faces a mandatory life prison sentence. He showed no emotion as the verdict was delivered. The jurors had earlier indicated they were split but continued to deliberate. Defence lawyer Amy Thompson said she would appeal against the verdict. "It has always been our position, and it still is, that William Balfour is innocent of these murders," she said. At the time of the killings, Balfour was estranged from Ms Hudson's sister, Julia Hudson. Prosecutors had to build an overwhelming circumstantial case against him as there were no surviving witnesses or fingerprints to link him to the crimes. They said that when Julia Hudson left home for her job as a bus driver on the morning of 24 October 2008, Balfour went into the home and shot Ms Hudson's mother, Darnell Donerson, 57, in the back, and then shot Jason Hudson, 29, twice in the head as he lay in bed. Prosecutors said Balfour then drove off in Jason Hudson's car with Julia's son, Julian King, and shot the boy several times in the head as he lay behind a front seat. The boy's body was found in the abandoned vehicle after a three-day search. Balfour had denied all the charges. His defence lawyers had claimed the killings could have been related to alleged drug dealing by Ms Hudson's brother. Ms Hudson, 30, a finalist on the 2004 series of American Idol, won an Oscar in 2007 for her supporting role in the musical Dreamgirls. She also sang I Will Always Love You at the Grammy awards this year in memory of the late Whitney Houston. In court, she was accompanied by her long-time partner, professional wrestler David Otunga. When she testified in April, she said none of her family had wanted her sister to marry Balfour. "We didn't like the way he treated her, and I didn't like the way he treated my nephew," she told the court.