A lawyer for Brendt Christensen, who is charged with kidnapping and killing Chinese scholar Zhang Yingying in 2017, told a Federal judge on Wednesday morning that Christensen has admitted killing her.

"Brendt Christensen is responsible for the death of Yingying Zhang," said Christensen's defense attorney George Taseff in US District Court in Peoria, Illinois as Christensen's trial started.

Taseff said the trial will be an effort to spare Christensen, 29, the death penalty.

In detailing the crime, prosecutors said Christensen picked up Zhang, bound her hands and took her to his apartment where he raped her and choked her for 10 minutes while she fought for life. He then put her in a bathtub, hit her in the head with a baseball bat, breaking open her head, decapitated her and then disposed of the remains at an unknown location.

Christensen has been held without bond since he was arrested in June 2017 for the abduction and presumed slaying of Zhang, a 26-year-old student at University of Illinois at Urbana-Champaign. Her body has not been found.

A onetime master's student at the university, Christensen, has been charged with murder, kidnapping and lying to federal investigators. He pleaded not guilty to all counts.

Zhang came from southeastern China to study photosynthesis and crop production at the university two months before she was reported missing on June 9, 2017. A professor and several of her classmates told police they were unable to contact her for hours, authorities said.