Chicago (CNN) -- Jurors began deliberating Wednesday in the trial of a man accused of killing the mother, brother and 7-year-old nephew of entertainer Jennifer Hudson.
Heated closing arguments set a tense tone in the courtroom before the judge sent the 12-person jury into deliberations.
The singer-actress kept her head down during much of Cook County prosecutor Jennifer Bagby's dramatic closing argument.
Showing autopsy photos of the victims, Bagby pointed toward William Balfour, Hudson's former brother-in-law.
"It's time to hold him responsible," she said.
Hudson dabbed her eyes with a tissue as the prosecutor listed the charges: first-degree murder, home invasion, residential burglary and possession of a stolen vehicle.
Balfour has pleaded not guilty to the charges, and his lawyer has argued that there is no forensic evidence linking him to the killings.
"They have failed to prove their case," defense attorney Amy Thompson said during her closing argument Wednesday, her voice rising. "He is on trial for his life."
Thompson argued that police homed in on Balfour rather than conducting a full investigation.
"In their mind, this wasn't a whodunnit," she said.
No DNA evidence found points to Balfour, said Thompson, who also questioned police work in the case, describing a set of keys that she said surfaced on an evidence list a month after the slayings.
"Those keys show how desperate the state was. They resorted to this. ... My client is an innocent man," she said.
But prosecutors argued that physical and circumstantial evidence clearly links Balfour to the killings and said defense claims that police may have planted evidence or been part of a conspiracy to frame Balfour were "absurd."
Prosecutor Jim McKay told jurors that there was a "tsunami of circumstantial evidence."
"The circumstantial facts of this case are drowning this guy in guilt," he said.
Bagby said in her closing argument Wednesday that Balfour had threatened to kill the family of Julia Hudson, Jennifer Hudson's sister.
"If you leave me, I'll kill you. I'll kill your family first. You'll be the last to die," he had said, according to Bagby.
"He went in that house for one reason, and one reason only, to carry out that threat," Bagby told jurors.
Balfour is accused of fatally shooting Hudson's mother, Darnell Donerson, 57, and the singer's brother, Jason Hudson, 29, in their Chicago home in October 2008. The body of Hudson's 7-year-old nephew, Julian King, was found three days later in an abandoned vehicle.
Prosecutors have portrayed Balfour as a jealous man who murdered three people in a rage at the thought that his wife had a boyfriend.
In her closing argument, Bagby said Balfour shot Hudson's mother as she tried to defend herself with a broom.
"He fired that gun at her over and over and over," Bagby said.
McKay called Balfour "a true coward."
"He shoots a 57-year-old grandmother in the back. He shoots a 29-year-old man in his sleep. He shoots a 7-year-old twice in the head," McKay told jurors. "The family, the community, the city, the country demand justice."
Deliberations of the jurors -- six men and six women -- were scheduled to last until 9 p.m. before breaking for the day Wednesday.
There have been 83 witnesses and 11 days of testimony in the trial.
Hudson, who was on hand through the trial, was called as the prosecution's first witness. She broke down in tears several times on the stand as she recalled her family.
"None of us wanted her to marry him," Hudson said of her sister's decision to marry Balfour. "We did not like how he treated her.
"Where he was, I tried not to be," she said.
The deaths took place a year after Hudson, who rose to fame as a contestant on "American Idol," won an Oscar for her role in the movie "Dreamgirls."
In a recent interview with CNN's Piers Morgan, Hudson reflected on the life of her mother.
"My mother was a very wise and strong person. I feel like she raised us well, and she prepared me well, and so that's what I live by," she said.
Her career has continued to blossom and remains varied since her relatives' deaths.
Recent milestones include penning a memoir detailing her struggles with her weight; being cast as Nelson Mandela's ex-wife, Winnie, in an upcoming movie; releasing a new album; and singing a well-received tribute to Whitney Houston at the Grammy Awards in February.
CNN's Katherine Wojtecki contributed to this report.