BRENDT CHRISTENSEN, accused of kidnapping and killing Zhang Yingying, a missing Chinese visiting scholar, was obsessed with Ted Bundy and other serial killers, U.S. prosecutors said Wednesday, as they shared with jurors grisly details of how the victim was allegedly raped and brutally beaten before her death in a case closely watched by Chinese students across the United States and beyond.

Shocking observers only moments into his client’s capital trial, U.S. federal defender George Taseff representing Christensen admitted Christensen killed Zhang.

“Brendt Christensen is responsible for the death of Yingying Zhang,” Taseff told a packed court Wednesday inside the Peoria federal courthouse. “Brendt Christensen killed Yingying Zhang.”

Despite the admission, Christensen, a former Ph.D. student researcher from the University of Illinois, is not changing his not guilty plea. The trial will continue, Taseff said, because Christensen is “on trial for his life” and there are several “factual issues” that must be debated before sentencing.

He is charged in federal court with kidnapping resulting in death and lying to FBI investigators. If convicted, he faces a possible death sentence.

Zhang, a 26-year-old visiting scholar studying photosynthesis and crop productivity at the University of Illinonis, was last seen alive June 9, 2017.

Surveillance footage showed Zhang entering a car allegedly driven by Christensen just after she missed a bus en route to sign a lease off campus. She has not been seen since and her body has not been recovered.

Christensen abducted Zhang to his apartment where she fought for her life as he raped her, hit her over the head with a baseball bat, and stabbed her in the neck before cutting off her head, Eugene Miller, an assistant U.S. attorney for central Illinois, said Wednesday.

“Her blood ran down the wall,” the prosecutor said, as some of Zhang’s relatives sat in court listening to an interpreter through headsets. “Thousands of miles away from her parents, alone with a stranger, she breathes her last breath.”

Christensen appeared in court wearing a blue shirt, with his hands cuffed behind his back. Growing up in north central Wisconsin, the United States, Christensen was a smart, friendly boy — the sort of child neighbors recall years later with bland fondness.

He did well enough in high school to study physics at the University of Wisconsin, then went on to graduate school at the University of Illinois at Urbana-Champaign. There, he was in the prestigious doctorate program for a time and, working as an instructor, was so well-liked that he was rated outstanding by students.

Miller said Christensen had begun planning to abduct and murder someone months before he ever saw Zhang. He had researched online how to abduct someone before buying a very large duffel bag.

Christensen compared himself to serial killer Bundy, who killed dozens of women in the 1970s, Miller said during his opening statements, and he bragged to his girlfriend that “I’m pretty good at this,” after investigators failed to locate Zhang’s remains.

Christensen posed as an undercover officer to convince Zhang to get into his vehicle, Miller said, before taking her back to his apartment. There, he allegedly cut off her clothes and raped her before choking her for about 10 minutes, according to Miller, while Zhang continued fighting for her life.

He then took Zhang to his bathroom, where he allegedly hit her in the head with a Louisville Slugger baseball bat, splitting open her head. Christensen ultimately stabbed her and cut off her head, Miller said.

Miller said Christensen cleaned his apartment and vehicle extensively in an effort to cover up his crime. But investigators located blood spots on his mattress and the baseboard of his bed, as well as on drywall, underneath his carpet and on the baseball bat.

DNA testing conducted on these samples matched the blood to Zhang.

“He kidnapped her, he murdered her, he covered up his crime,” Miller said.

Zhang’s father and other family listened to these statements in the courtroom through an interpreter. Christensen, who was seated at his defense table, did not appear to react.

Details of Zhang’s murder were apparently learned through a recording made by Christensen’s girlfriend, who was cooperating with the FBI and wore a wire to record their conversations, including during a vigil walk for Zhang.

On that recording, Christensen allegedly said he wanted to attend the vigil “to see how many people are here,” he said. “They’re here for me.”

He also added that Zhang’s body would never be found and that her family, who had traveled from China to help locate her, would be “leaving empty handed.”

Taseff denied few of these details, but did take issue with the fact Christensen said on the recording that Zhang was his 13th victim. The attorney claimed Christensen had been drinking heavily before the vigil, adding that there is no evidence to show Christensen had ever killed anyone before Zhang.

Taseff told the jury he did not dispute that Christensen killed Zhang, which he called “a horrible crime.” But Taseff said he took “serious issue” with the government’s account of events.

“You need to know who Brendt was and what he was going through — a downward spiral in his life,” Taseff told the jury as he sought to protect his client from the death penalty. Taseff described Christensen as a man who turned to alcohol and drugs as he struggled with an unhappy open marriage and a painful relationship with a girlfriend.

On the day of the killing, “he hits ground zero, rock bottom,” Taseff said, noting that Christensen had learned that his girlfriend was with another man that morning.

Christensen bought a bottle of rum from a liquor store at about 7:45 a.m. before driving around while drinking, Taseff said.

“At 2 o’clock in the afternoon,” Taseff said, “he does the unthinkable.”

Among the first witnesses to testify Wednesday were Zhang’s parents, and Hou Xiaolin, Zhang’s boyfriend.

The father was in court, while the mother was in an overflow room, the News-Gazette reported.

Zhang’s mother, Ye Lifeng, told ABC News in a recent interview about her reaction when she heard of Christensen’s arrest, saying, “I wanted to kill him at the time.”

“I cannot believe there is such an evil person among us in this world,” Zhang’s father, Zhang Ronggao, added. “I think he should definitely get the death penalty.”

Hou described the “shock” and “terrible” feeling of learning his girlfriend had disappeared.

Hou and Zhang Yingying first met while studying together in Sun Yat-sen University in 2009.

They were in the same classes, and eventually finished No. 1 and No. 2 in their graduating class in 2013. The pair continued their education at Peking University in China, where they continued dating.

Hou testified they were planning to get engaged and married in October 2017, about four months after Zhang disappeared.

Once he learned Zhang had gone missing, Hou traveled with his girlfriend’s family to the United States to help search for her. He testified they looked in parks and abandoned houses around the Champaign-Urbana area, but never found her.

“We were searching for her all the time,” Hou testified. “We’d never give up hope we’d find her.”

The federal death penalty case is the first in Illinois since the state struck capital punishment from its books on the grounds that capital punishment processes were too error-prone.

Zhang’s mother told ABC News she now hopes to learn Christensen did not take her daughter’s life.

“I hope he would give my daughter back to me,” she said.(SD-Agencies)