Yingying came to Urbana, IL, from China to complete her doctoral studies with the dream of becoming a professor. She was last seen in 2017, getting into Christensen’s car. Her body was never found. It was a mix of surveillance footage, online search histories, and incriminating statements recorded by the FBI with the help of Christensen’s girlfriend that led to his arrest. In the recordings, Christensen described in detail how he killed Yingying and claimed no one would ever be able to find her body. Christensen’s former girlfriend has yet to take the stand, but she is expected to be a star witness for the prosecution.