A memorial stone engraved with Yingying Zhang’s name in both English and Chinese on the campus of the University of Illinois at Urbana-Champaign in June 2019, two years after her disappearance. (Photo by Mark Van Moer) Inset, top: Yingying Zhang (Courtesy University of Illinois Police Department). Bottom: Brendt Christensen (Courtesy Macon County Sheriff’s Department).

Brendt Christensen appeared “excited” and laughed when talking about killing Yingying Zhang, his former girlfriend testified Thursday at Christensen’s death-penalty trial.

Yingying Zhang disappeared on June 9, 2017. (University of Illinois Police Department). Inset: Brendt Christensen (Macon County Sheriff’s Department)

During testimony Wednesday, Terra Bullis described her past relationship with Brendt Christensen and how she came to wear a wire for FBI investigators who believe he is responsible for the disappearance of Chinese scholar Yingying Zhang.