Brendt Christensen, the manat the University of Illinois, allegedly spoke about what makes an "ideal victim." A prosecutor described the alleged comments at Christensen's second court hearing Wednesday. Prosecutors also told the court that Christensen was recorded allegedly describing how Zhang "fought and resisted" during her abduction.
Christensen is being held without bond after the June kidnapping.
A criminal complaint cited one instance where Christensen allegedly discussed abducting Zhang. Now we're learning other recordings were taken during the two-week period the FBI monitored Christensen before his arrest, reports CBS News correspondent Anna Werner.
The U.S. attorney said that at a vigil for Zhang attended by Christensen, he described "the characteristics of an ideal victim" and may have even possibly pointed out people he considered other potential victims in the crowd.
Former FBI profiler Mary Ellen O'Toole said suspects sometimes do show up at events for victims.
"It could've made him feel very important," O'Toole said. "He knows that he is the person that's responsible for all of this fear… and another reason that he could go to a vigil is to find out what's going on in the investigation. If you go to the vigil and you leave the vigil, in his mind he's not arrested, so maybe he's not developed as a suspect."
Attorneys for Christensen addressed reporters after the judge's decision Wednesday to keep him in custody without bond.
"We weren't surprised at the outcome of this hearing," attorney Evan Bruno said, adding, "It's not unusual for bail to be denied."
A criminal complaint alleges Christensen admitted to investigators he gave an Asian woman a ride the day of Zhang's June 9 disappearance – but said he let her out of his car.
Last week investigators said they don't believe the 26-year-old Chinese scholar is still alive. The announcement came as a blow to Zhang's family who flew to the U.S. from China after she disappeared.
"They still have the hope," Zhang family attorney Zhidong Wang said. "No one told them it's 100 percent. No one told them we have the body yet. They still, deeply in their mind, Yingying might still be alive somewhere."
The family's attorney tells CBS News that if Christensen is convicted, the Zhang family wants him to get the death penalty.
A crowd gathered outside the courthouse Wednesday with signs supporting Zhang. The Zhangs are conducting their own search for Yingying.