Police have charged a man in the disappearance of a University of IL visiting Chinese scholar.
The court document indicates a search of Christensen's auto indicates the area where Zhang was believed to have been sitting had been cleaned.
Investigators with the Federal Bureau of Investigation think the student, Yingying Zhang, 26, is probably dead, a news release from the attorney's office said.
Authorities also got hold of Christensen's cell phone and found that he had visited threads titled "Abduction 101", "perfect abduction fantasy" and "planning a kidnapping" on a fetish website called FetLife, according to the affidavit in the criminal complaint.
Asked if authorities had any leads as to where Zhang's body might be located, the spokesman for the FBI Springfield office, Bradley Ware, declined comment.
Some 5,600 Chinese are enrolled at U of I. On June 9, Zhang disappeared, only a few weeks after she had arrived in IL, to pursue studies in agricultural and environmental sciences.
In Friday's press release, authorities identified Christensen as the driver of the Saturn Astra, saying he was identified by security video.
Zhang, 26, went missing on June 9, about a month into a year-long assignment at the university's Urbana-Champaign campus where she was researching photosynthesis and crop productivity, Associated Press reported at the time.
Christensen remained in custody pending an initial federal court appearance, set for Monday in Urbana.
According to the affidavit, agents overheard him admitting to kidnapping Zhang.
The FBI has arrested a man they say kidnapped missing U of I scholar YingYing Zhang. Video from a security camera on the university campus showed her climbing into a auto and being driven away. The investigators were struck by Christensen's answer that he could not recall what happened in his life the day Zhang was last seen alive, on June 9.
"We realize that this has been a source of anxiety for our entire campus community", Jeff Christensen, chief of the university's police force, has said.
The FBI begins continuously montioring Christensen. Zhang's father, Ronggao, gives this message to the person who took Yingying: "Just give my daughter back". This undated photo provided by the University of Illinois Police Department shows Yingying Zhang. Further charges could be pending, as the investigation progresses and new evidence is discovered.