The FBI is investigating the claim by a former University of Illinois doctoral student that Yingying Zhang, the visiting scholar from China he's charged with killing was his 13th victim.
The second week of Brendt Christensen's trial began as the first week ended — with the focus on conversations between Christensen and his girlfriend that were secretly recorded, while authorities were conducting a massive manhunt for Zhang. Authorities say the woman agreed to be a confidential source for law enforcement shortly after Christensen posed as an undercover officer to lure 26-year-old Zhang into his car as she headed to sign a lease off campus, and kidnapped her.
On Friday, the federal jury listened to the recordings, hearing Christensen describe in gruesome detail how after he brought Zhang to his apartment, hit her in the head with a baseball bat, tried to choke her, stabbed her and finally decapitated her.
In the tape, Christensen never explicitly claimed that he killed 12 other people. However, he can be heard telling his girlfriend that she isn't in danger of becoming his next victim, explaining that she is too big. "It's about getting rid of 100 pounds versus 150 pounds," he said. "That's too much ... to get rid of."
Miller told jurors last week about Christensen's claim regarding additional victims but didn't offer additional details, nor did he say if authorities believed him. Miller appeared to broach the issue in order to demonstrate Christensen's quest to be known as a serial killer.
Christensen became obsessed with serial killers in the months before for he kidnapped Zhang, Miller said, adding that Christensen was engrossed by the novel "American Psycho" and was intent on slaying someone in order to fulfill a goal of infamy that he'd set for himself. Zhang, who had only been in Illinois for two months in what was her first experience living outside China, aspired to become a professor in her home country to help her working-class parents.
On Monday another witness, FBI Senior Forensic Examiner William O'Sullivan, talked about that fascination, telling jurors that in the weeks before Zhang disappeared, Christensen researched serial killers online.
Also testifying at the trial Monday was a police detective who told the jury that Christensen's demeanor and appearance changed dramatically when confronted with inconsistencies in his version of events.
University of Illinois Police Detective Eric Stiverson said Christensen began to tremble, break out in hives and appeared to hyperventilate under when he was confronted with inconsistencies in his version of events.
Christensen, now 29, never revealed in the recording what he did with Zhang's body, which has never been recovered. In one of the tapes, Christensen vowed never to tell anyone what he did with the body and said it will never be found.
Christensen is charged with kidnapping and killing her, which carries a possible federal death sentence. Last week, his attorneys, in attempt to prevent him from being executed, told jurors that Christensen had, in fact, killed Zhang.