'We were doing everything we could to try to determine where Yingying was,' agent Joel Smith testified Thursday, the second day of the prosecution's case against Brendt Christensen, who is accused of kidnapping and killing her. PEORIA — In the weeks after Yingying Zhang went missing, FBI agents and University of Illinois police officers searched through garbage at Centennial Park, an isolated area near Olympian Road and Interstate 57 and at the Murdock Mine 30 miles south of Champaign. They went there based on tips and pings from Christensen's phone, but repeatedly came up empty. read more