Brendt Christensen (Photo: AP)

PEORIA, the United States, July 17 (Xinhua) -- After prosecutors and the defense finished their separate closing arguments, a US judge on Wednesday afternoon began deliberations on possible death penalty for Brendt Christensen, who was found guilty of killing Chinese scholar Zhang Yingying in 2017.

The closing arguments of the sentencing phase for Christensen took place around 9 a.m.(1400 GMT) Wednesday at a federal court of Peoria, in the US state of Illinois.

The courtroom was full of people, with over 10 people watching the closing arguments from an overflow room.

Zhang Yingying's father, mother, brother and boyfriend showed up in the main courtroom in the morning, but after some deliberation in chambers, the mother didn't return.

Christensen's mother and father were also in attendance. He frequently looked at them and smiled. He was wearing a white dress shirt and dark gray pants.

Prosecutor James Nelson argued in the statement that "justice must be done" and asked "Is this a minimum sentence case?"

He acknowledged the grief of Christensen's family if he would be sentenced to death, but said the "source of that pain sits in that chair," referring to Christensen.

Nelson described the impact on Ms. Zhang's family, as they had placed great hopes on her.

"That's why Yingying fought so hard. She had so much to live for," he said.

Even if the jury chooses a sentence of life behind bars, he will be leaving prison "in a coffin," defense attorney Elisabeth Pollock told the jury in her closing statement.

The defense attorneys have "stood with Brendt for almost two years," Pollock said tearfully, leaving the lectern to stand behind Christensen.

"Remember he is a whole person," Pollock said. "He is not the worst thing he ever did."

Christensen was a gentle child, a good brother and friend and a "rule follower" for most of his life, Pollock said.

File photo: VCG

The defense team highlighted mental illness and substance abuse on both sides of Christensen's family, including his mother's depression and severe alcoholism when he was a child.

After the closing arguments, jurors in the capital trial of Christensen began deliberating over his appropriate sentence: life in prison or death. It may take several hours or even one to two weeks for the jury to make the final decision.

The jury last month unanimously ruled that Christensen was guilty of all three counts of charge against him, namely, kidnapping resulting in the death of Zhang Yingying in 2017; and two counts of making false statements to the Federal Bureau of Investigation (FBI).

The 26-year-old Chinese scholar went missing on June 9, 2017, after getting into a black Saturn Astra about five blocks away from where she got off a bus on her way to an apartment complex to sign a lease.

Christensen was arrested on June 30, 2017, after being caught on tape pointing out people he described as "ideal victims" during a vigil in Zhang's honor.