True Crime Vault: Undercover Girlfriend

In June 2017, 26-year-old Chinese visiting scholar Yingying Zhang vanished after boarding a bus near the University of Illinois campus. Surveillance footage captured her getting into a black Saturn Astra driven by Brent Christensen, a quiet physics graduate student with no criminal record. What followed was a high-stakes investigation that pivoted on a single, overlooked detail: a missing hubcap on the car’s right front wheel. That tiny clue led investigators to Christensen, who initially denied involvement but later admitted to picking up Zhang. Under intense interrogation and with his girlfriend Tara Bullis wearing a wire, Christensen made chilling admissions—on tape—that he had abducted, murdered, and dismembered Zhang, even claiming to have killed others before. Despite overwhelming evidence, including DNA on a baseball bat and cleaning supplies bought at Walmart, Christensen was not sentenced to death due to a hung jury. He received life in prison, but the case remains unresolved for Zhang’s family, who still seek her body and a traditional burial. The tragedy deepens with revelations that Christensen had sought counseling just weeks before the crime, checked a box indicating homicidal thoughts, and was flagged—but never followed up on—by university staff. The family has since filed a civil lawsuit against the university’s counseling center, arguing that the tragedy could have been prevented.