PEORIA, Ill. — An Illinois man accused of kidnapping and killing a graduate student from China two years ago was obsessed with Ted Bundy and other serial killers, a federal prosecutor said on Wednesday on the first day of the trial of the sensational case.

Brendt Christensen, 29, could face the death penalty if he is convicted in the June 2017 abduction and murder of Yingying Zhang, a 26-year-old student at the University of Illinois at Urbana-Champaign, 130 miles south of Chicago. Zhang’s body has never been found.

Christensen’s defense lawyer acknowledged in his opening statement that his client killed Zhang but disputed the prosecution’s version of events.

“You need to know who Brendt was and what he was going through — a downward spiral in his life,” George Taseff told the jury as he sought to protect his client from the death penalty.

While the state of Illinois has outlawed capital punishment, a federal trial allowed prosecutors to seek the death penalty.

Christensen, who received a master’s degree in physics from the university, has been charged with murder, kidnapping and lying to federal investigators. He has pleaded not guilty to all counts.

Christensen appeared in court wearing a blue shirt, hands cuffed behind his back. The trial is being held in Peoria, 90 miles northwest of Champaign-Urbana.

Eugene Miller, an assistant U.S. attorney for central Illinois, said Christensen was obsessed with Bundy, who killed dozens of women in the 1970s, and other serial killers.

“He kidnapped her, he murdered her, and he covered up the crime,” Miller told the jury in his opening statement.

Before the crime he had researched how to abduct someone and purchased a very large duffel bag, he said. On the day of the murder, Christensen was looking for a victim when he found Zhang, who was small and spoke limited English, Miller said.

Christensen took Zhang to his apartment where she fought for her life as he hit her over the head with a baseball bat.

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

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

Taseff said Christensen had 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, after learning 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., then drove around while drinking, Taseff said.

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