PEORIA, Ill. — The legal battle over whether a former University of Illinois doctoral student should live or die for the kidnapping and slaying of a Chinese scholar began with a prosecutor on Monday telling jurors that the crime was so vicious that the death penalty is warranted.

”It was cold, calculated, cruel and months in the making,” Assistant U.S. Attorney James Nelson told jurors on Monday afternoon.

Reminding jurors that Brendt Christensen has never revealed what he did with Yingying Zhang’s body after he brutally killed and decapitated her in June of 2017, Nelson spoke of what that has meant to the still-suffering family of the young woman.

”There will be no burial. There will be no closure,” he told the jury that last month found Christensen guilty. “You will see the anguish.”

But The (Champaign) News-Gazette reported that in the effort to convince jurors to spare the 30-year-old Christensen’s life, a court-appointed attorney called by the defense attorneys tried to convey to them that a sentence of life in prison without the possibility is punishment enough.

Christensen “will die in prison, alone, with strangers,” said Julie Brain. “The only question that remains is when his death occurs — at the end of his natural life or at a date the government chooses.”

Defense attorneys were expected to detail Christensen’s mental problems in the hopes of convincing the jury to spare Christensen’s life and Brain did just that. She explained how Christensen has struggled with mental health issues such as night terrors and debilitating migraine headaches his whole life. And she told of how Christensen did not get the help he needed when he sought mental health treatment at the U of I.

The opening statements come after a morning hearing in which the judge told the attorneys he would allow jurors to watch videos made by Zhang’s mother, several of her friends, as well as watch a video that shows Zhang singing.

The beginning of the penalty phase of Christensen’s trial comes days after the same jury found Christensen guilty . During the current hearing, Christensen’s attorneys — who acknowledged at the beginning of the trial that Christensen was guilty — will argue that their client’s life should be spared. They are expected to tell jurors that Christensen knew his homicidal fantasies months before he killed Zhang weren’t right and sought help from U of I mental health counselors. They have alleged the school didn’t do enough to help.

But prosecutors have already during trial told jurors that Christensen in June 2017 kidnapped Zhang from a bus stop, took her into his apartment in a duffel bag where he raped, stabbed and choked her before beating her to death with a baseball bat. They could use that information to show Christensen’s meticulous planning of the crime and how he even seemed to express pride in what he had done to argue for the death penalty — something Zhang’s family members already have said they support.

On Monday, the judge also said he would allow jurors to hear a recording of a phone call that Christensen made from jail. Prosecutors told the judge Monday that Christensen asserts his innocence — something The (Champaign) News-Gazette reports that prosecutors want jurors to hear because they believe it shows Christensen’s lack of remorse.

The 30-year-old Christensen could testify during the hearing that is expected to last several days. If he does, one big question is whether he will reveal what he did with Zhang’s body, which has never been found, as part of an effort to convince jurors to spare his life and sentence him instead to life in prison without the possibility of parole.