Balfour is charged in the murders of Jennifer Hudson's three family members. Her nephew, mother and brother were killed in 2008. Balfour was married to Hudson's sister, Julia.
On day four of the trial, witness Robbin Myers said two months before the murders he saw Balfour at a child's birthday party with Julia. At that time, Myers said Balfour appeared agitated and began to ramble about the Hudsons, threatening the family "at least 10 times." He told the jury Balfour said, "She doesn't like me, she doesn't want me around. She thinks she is better than everyone else." Myers also said he saw that the handle of a gun was in Balfour's waistband at the party.
Balfour is accused of using a gun that belonged to Hudson's brother, Jason, in the murders.
Myers didn't speak to police or the state's attorney's office until they contacted him last year.
Also on Thursday, Balfour's ex-girlfriend Diana Grant was called to testify. She said she spent several nights with Balfour at an apartment across the street from the Hudson's Englewood home. Grant said two months into their relationship she found out Balfour was married to Julia Hudson.
Jennifer and Julia Hudson sat together with Jennifer's fiance in the courtroom Thursday. Court was adjourned for the day just after 4 p.m.