Brendt Christensen. /Southern Metropolis Daily Photo

US Magistrate Judge Eric Long on Monday ordered the man accused of kidnapping a visiting Chinese scholar to be held without bond until his next court hearing on July 5.

Brendt Christensen, 28, charged with kidnapping Zhang Yingying on June 9, did not speak during a hearing at a federal courthouse in Urbana, Illinois.

If convicted of the federal kidnapping charge, Christensen potentially faces life in prison, according to Sharon Paul, a spokeswoman for the US attorney's office.

Christensen was enrolled as a Ph.D. candidate in experimental condensed matter physics by the University of Illinois at Urbana-Champaign (UIUC), but it was not clear if he was still studying at the university when he was arrested on Friday.

Wearing an orange jumpsuit, Christensen did not speak during the hearing that lasted nine minutes, other than to acknowledge that he understood his rights, according to local media ABC7.

Judge Long asked Christensen's attorney, Evan Bruno of the Urbana-based Bruno Law Firm, whether he was ready to take a stand on bail. When Bruno asked for a few days, Long set a detention hearing for 3 p.m. Wednesday, during which bond conditions will be determined.

(This undated photo provided by the University of Illinois Police Department shows Zhang Yingying. /University of Illinois Police Department Photo via AP)

Christensen will be held in the custody of the US Marshals Service before the detention hearing.

A preliminary hearing was set for 10 a.m. local time on July 14. It would be waived if a grand jury returns an indictment before then.

About 45 people packed the courtroom, with hundreds of Chinese from Zhang's university and the local Chinese community gathering in the courthouse lobby and outside across the street.

They held posters written "Bring Justice to Yingying and her family," chanting "Justice for Yingying."

Zhang Yingying's father breaks down during an interview with Illinois local media. /Screenshot of The News-Gazette interview

Zhang, 26, went missing on June 9 after she got into a black Saturn Astra car about five blocks from where she got off a bus as she was heading to an apartment complex to sign a lease. Police believe Zhang, who arrived at the University of Illinois in late April, is no longer alive.

FBI and local policemen arrested Christensen last Friday evening based on the fact the suspect called someone about his kidnapping of Zhang.

"While Christensen was under law enforcement surveillance, agents overheard him explaining that he kidnapped Zhang," an FBI press release said.