A birthday gift made homicide suspect William Balfour so jealous he killed three family members of actress Jennifer Hudson in Chicago, prosecutors allege.

Prosecutors have suggested Balfour found a gift to his estranged wife Julia, Hudson's sister, and suspected it came from another man, causing him to fly into a rage that left the "Dreamgirls" star's mother, brother and nephew dead, People.com reported Saturday.

Balfour, 27, was arrested Oct. 23, the same day the killings occurred, but his attorney alleges he will be exonerated.

"We are extremely confident that once all of the evidence has come to light and has been tested by our vigorous analysis of the case, that William will be found not guilty," attorney Joshua Kutnick said at a recent bail hearing.

Prosecutors allegedly have physical evidence tying Balfour to the deaths of Hudson's 57-year-old mother Darnell Donerson, her 29-year-old brother Jason and 7-year-old nephew Julian King,

But Police Superintendent Jody Weis told People without a confession from Balfour, a conviction is not a certainty.

"You never know how a jury is going to decide cases, so whenever you go to trial, it is somewhat a roll of the dice," Weis said.