During the trial Hou exchanged emails with Christensen's father.

"I asked if we could meet Christensen in person after the trial," Hou says. "I had always harbored hope that he might be driven by whatever remains of his humanity to tell us the truth. Christensen's father didn't give any definitive answer. But when I tried to contact him again after the trial he didn't reply."

In August, on Shi's behalf, two fellow alumni from Peking University visited the Zhang family in Fujian province, bringing with them a computer on which they showed the parents Shi's documentary. Throughout one of them held the mother tightly.

For Sun, the movie represents an effort to "look beyond the stereotype". "In American mainstream media we overseas Chinese students often appear as a group, a number, whose individual members are seldom given the attention they deserve. This is especially true in a central state like Illinois, where high unemployment has antagonized some against immigrants and foreign students."

Minutes before Zhang got into Christensen's car, she failed to catch a bus. A camera on that bus shows her running behind it...

In January last year Miao Guofang, with whom Zhang spent the most time during her stay in Illinois, paid her last tribute to the dear friend lost, before she left the US permanently to take up a teaching post in a Chinese university. In freezing cold, Miao tied a golden bell to a tree standing where Yingying was before she got into that car.

"Guofang and I have a lot in common...both of us confront problems head-on,"Zhang wrote in her diary."But I may compromise, I may want to be famous..."

In the summer of 2018, while waiting at home in China for the trial to begin, Ye Lifeng joined a local Christian church."Why must my daughter die? I asked myself and everyone I knew. Now I leave this question to God."