An emotional Jennifer Hudson took the stand Monday in the trial against estranged brother-in-law William Balfour, the man accused of killing her mother, brother and nephew, the Associated Press reports.  

The Oscar-winning actress was the first to testify, recalling how she had warned her sister, Julia Hudson, to stay away from Balfour. "None of us wanted her to marry him," she said, holding back tears. "We did not like how he treated her."

Jennifer Hudson's brother-in-law pleads not guilty to murder charges in family slayings

Hudson's mother, Darnell Donerson and her brother, Jason Hudson, were found shot to death in October 2008. The body of Jennifer Hudson's 7-year-old nephew, Julian King, was found days later in a vehicle miles from their home. Balfour pleaded not guilty in early 2009 to murder charges.

Julia Hudson also testified, noting that Balfour would get so jealous, he would get angry if her son showed affection. "He'd say, 'Get off my wife,'" Julia told the jury. She also discussed the many threats he made against her. "He said, 'If you leave me, you will be the last to die. I'll kill your family first,'" she said.

After testifying, Hudson joined her fiancé, David Otunga, to watch the rest of the trial, which is expected to last about a month.