CHICAGO (AP) — The girlfriend of an ex-University of Illinois student charged with kidnapping a visiting scholar from China says he seemed proud as he told her he killed Yingying Zhang.

Star prosecution witness Terra Bullis testified Thursday for a second day at Brendt Christensen’s trial. He told her he raped and then beat the 26-year-old to death.

Bullis secretly recorded Christensen as they attended a vigil for Zhang. The FBI arrested him the next day.

Champaign’s News-Gazette reports Bullis told jurors Christensen’s eyes widened and seemed eager to provide details.

He told her Zhang was his 13th victim, writing the number 13 on her hand. Investigators haven’t been able to corroborate the claim.

She says he also pointed to a woman at the event, saying she’d be “a good target.” He said they could follow her but never did.