A US federal grand jury indicted a 28-year-old former physics doctoral student on Wednesday in the June 9 kidnapping of visiting Chinese scholar Zhang Yingying.

Brendt Christensen, 28, of Champaign, Illinois, who has a master's degree in physics from the University of Illinois at Urbana-Champaign, was arrested on June 30 on a charge of kidnapping Zhang, 26, who was attending the same school.

On July 5, he was ordered held without bail by US Magistrate Judge Eric Long of the US District Court for the Central District of Illinois in Urbana. Christensen will be arraigned on July 20 in Urbana, and his lawyers have said he will plead not guilty. If convicted, he faces a maximum penalty of life in prison.