PEORIA, Ill. (WAND)- DNA found in Brendt Christensen's apartment likely comes from Yingying Zhang, an FBI forensic examiner told jurors Wednesday.
Researchers identified a stain on the underneath portion of carpet removed from Christensen's bedroom as blood, forensic examiner Amanda Bakker testified. Researches found DNA from one person on that sample, and it was 97 octrillion times more likely it came from Yingying Zhang as anyone else.
Forensic examiners obtained what they believe to be Yingying Zhang's DNA from three toothbrushes at her apartment.
A baseball bat found in Brendt Christensen's apartment also tested positive for DNA consistent with Zhang, although investigators did not detect blood on the bat through testing, Bakker said.
Swabs of three stains on mattresses in Brendt Christensen's bedroom also tested positive for DNA from three people, and Bakker said Yingying Zhang was the likely contributor of DNA for all three.
In cross-examination, Christensen's attorney pointed out forensic examiners tested several items from Christensen's bathroom for DNA, but only the sink-trap tested positive for DNA, which did not match Yingying Zhang's.
Christensen's trial resumed at 1:30 p.m. Wednesday, after Judge James Shadid attended funeral services for Peoria County State's Attorney Jerry Brady.
Later in the afternoon, Brendt Christensen's girlfriend in 2017 took the stand.
Terra Bullis told jurors she began dating Christensen in April 2017 after the two met on a dating website. The two had their first date soon after.
"Our first date was whimsical," she said. "He seemed kind, courteous, amicable. I enjoyed spending time with him."
The two engaged in a sexual relationship that included BDSM (Bondage, Domination, Sadism, Masochism), in which Christensen took on a dominant role and she took on a submissive role which included doing domestic work like cleaning Christensen's kitchen and bathroom.
Prosecutors asked Bullis about Christensen's use of a website called Fetlife and his username Akuma689. Bullis said Akuma refers to a Japanese fire deity or, among Japanese Christians, Satan.
Asked by prosecutors, she said Christensen drank to excess and did not seem to want to stop. She also said Christensen did not seem angry or violent when he was drunk.
Bullis also said Christensen made "multiple" statements to her about serial killers. She said he also discussed killing someone and not getting caught:
"It was a hypothetical conversation, but he described it could be easy," she said. "It could be done without people knowing."
On one occasion in May 2017, Christensen told her he was standing in line at a shoe store when a woman in front of him gave her address to the cashier. Christensen said he went to the address later but left, she said.
On June 9, 2017, the day Yingying Zhang was last seen, Bullis texted Christensen early in the morning to tell him that she had gone home with a man the previous night. At 6:31 a.m., Christensen texted back "No worries bunny".
At 4:53 that evening, Christensen texted: "How's your day been(?) I'm exhausted."
On June 15 and 16, FBI agents interviewed Bullis. She agreed to record her conversations with Christensen.
"I was emotionally attached to this person, and I wanted to know if they'd done that or not," she testified. "When I care about someone, I truly care about them, but I also cared about this missing person. It's painful."
In one conversation, Christensen told her he would give her more details on the case at a later date.
"It's just one of those things where, the less you know ....," he said. "I don't want you caught up in this more than you have to be."
In the same conversation, she mentions being asked about a large duffel bag. Christensen tells her that he had used a duffel bag to bring a cat tree to her home but that the cat tree broke and he left it outside where it may have been stolen.
In another conversation, Christensen told her investigators found blood on his mattress and baseball bat and suggests she could have bled on it during a sexual encounter.
In a conversation June 9, Christensen discourages Bullis from talking to investigators further.
"I'm going to recommend that you don't ... if they come and ask you questions, you just use your right to remain silent," Christensen said.