Jennifer Hudson's sister Julia "immediately suspected" ex-boyfriend William Balfour as the murderer of her family members.

A hearing was held earlier this week into the murders of Jennifer's mother, brother and nephew and the court heard testimonies from several people including a police officer.

Chicago police officer Jennifer Bryk testified that Julia knew Balfour was responsible for the murders. "She said he was upset over balloons that were in the house, that they were from another man," Bryk testified, according to BigPondNews.

She also revealed that a boy who lived on the same block as the family told police that Balfour had threatened to kill everyone in the family just a couple of weeks before he allegedly carried out the murders.

It emerged yesterday that Jennifer is to speak with the defence team before the trial begin in relation to text messages exchanged between her and her mother.

Balfour is to stand trial in April.