JENNIFER HUDSON's former brother-in-law killed three members of the Oscar winner's family because he was jealous about his ex-wife's new romance, according to prosecutors trying to jail the accused.

William Balfour has been charged with the October (08) slaying of Hudson's mother, brother and nephew - and lawyers representing the family feel sure they have a motive.

In a hearing on Wednesday (03Dec08), during which Balfour was denied bail, a Cook County prosecutor told a Chicago, Illinois court the accused confronted Hudson's sister Julia over her new romance before going on his killing spree.

Hudson's mother and brother were found dead at their home and the body of the singer/actress' seven-year-old nephew was found in an abandoned SUV three days later.

Balfour has been charged with three counts of first-degree murder, and had reportedly confessed to the crimes, according to Chicago Police.