A day after Jennifer Hudson‘s mother and brother were found murdered, a young boy remains missing while a possible suspect sits in custody.

Late Friday night, William Balfour - the singer’s estranged brother-in-law - was located by the Chicago Police Department hours after the bodies of 57-year-old Darnell Donerson (Jennifer’s mother) and 29-year-old Jason Hudson were found. Although no charges have yet been filed, officers identified Balfour as a person of interest in the murders and in the disappearance of Julian King, his 7-year-old stepson.

The crime scene was discovered yesterday afternoon when Jennifer’s sister, Julia Hudson, returned to the house after work. When police arrived to the South Side home, they found a woman with a gunshot wound to her head in the living room and a man with a gunshot wound to his chest in a bedroom. An Amber Alert was issued shortly thereafter for King. Based on earlier reports of gunshots fired, officers believe the incident may have actually occurred around 9:00 in the morning.

According to state records, Balfour, 27, was currently on parole after serving time for attempted murder and vehicular hijacking. He and Julia had been married for about two years, though they were apparently separated and headed for divorce.

As of Saturday afternoon, investigators said they were talking to “a number of people in custody.” Meanwhile, the FBI had been called into help out with the missing child search. Although Jennifer was reportedly headed to Chicago-area from Florida, the Oscar-winner’s whereabouts are currently unknown.

(You can follow updates to this story here.)