Zhang Yingying's family members meet the press near the federal courthouse building in Peoria, Illinois, the United States, on June 24, 2019. Brendt Christensen, a former doctoral student of the University of Illinois at Urbana-Champaign (UIUC), on Monday was ruled guilty of kidnapping and killing Zhang Yingying, a visiting Chinese scholar at UIUC, in 2017. (Xinhua/Wang Ping)