The estranged brother-in-law of former American Idol contestant and Oscar-winning actress, Jennifer Hudson has been arrested for the murders of her mother, brother and 7-year-old nephew.

William Balfour had only been named a 'person of interest' in the case until Monday. He had been married to Hudson's older sister. Police say Balfour has refused to take a lie detector test and has stopped cooperating with detectives in the case.

Balfour remains behind bars and is awaiting formal charges.