In graphic detail Christensen described to Bullis how he tormented and sexually assaulted her in his bedroom, before carrying her into a bathtub, where he hit her "as hard as he could with a baseball bat". Despite his seemingly uncontrollable urge to brag about the atrocity, Christensen expressed disbelief at the valiant defense of his victim, who even "reached up to grab" his hand as he stabbed her neck.

"She just didn't give up," said the killer, who eventually decapitated her.

One of the Zhang family's two lawyers, Wang Zhidong, partner of the Chicago law firm Wang, Leonard & Condon, was at the airport to meet Zhang's father, maternal aunt and Hou when they flew in on June 17, eight days after Zhang went missing. (For health reasons Zhang's mother was able to come to the US only in August, accompanied by her son, Zhang's younger brother.)

For the next two years Wang was with the family every step of the way as they negotiated the country's daunting legal labyrinth, heavy-hearted. "One of my main jobs was to try to make them understand the vast differences between the US and Chinese criminal justice system," he said."Given that the whereabouts of Yingying's body still remain unknown, it would have been extremely hard to convict Christensen if it was not for the secret recordings of their dialogues made by Bullis, who also turned up to testify in court when Christensen went on trial in June last year."