On a sweltering August Day in 2018 Hou Xiaolin stood below a second-story window of a vine-covered redbrick dormitory building in northwestern Beijing and looked up.

"This is where I would come and call out to her," he said.

Hou was speaking of his late girlfriend Zhang Yingying, who lived there from 2016 to 2017. In April 2017 Zhang, a research assistant for a scientist with the Chinese Academy of Sciences, left for the US to study for a doctoral degree at the University of Illinois at Urbana Champaign. There, on June 9, just two months after she arrived, she was abducted, raped and brutally killed by a man named Brendt Christensen.

From then until July 2019, when he was sentenced to life in prison, Hou had been through hell: he had gone on a needle-in-the-haystack search, clinging hopelessly to hope, had endured an unbearable wait, subdued all-consuming anger and prevailed over crippling frustration seeking justice for the woman he had planned to marry.

Yet on that summer afternoon in 2018, a little more than one year after Zhang's death, any signs of the toll that a long, continuing legal battle had taken on Hou were absent from his face. There was only softness－the kind one exudes reminiscing on what may seem like trifling details of life but that are nevertheless somehow reassuring.

"Occasionally, I would come here to pick up clothes for her," said Xiao, pointing to laundry hanging from a clothesline tied between trees.

Listening to this on the other side of a video camera was Shi Jiayan. With a master's degree from the journalism school of Northwestern University, Shi, with her partner Sun Shilin, followed Hou and members of Zhang's family between July 2017 and September 2019, shooting 300 hours of footage that was eventually edited down to 98 minutes in a documentary titled Finding Yingying.

This year Finding Yingying, Shi's debut feature documentary, was awarded the Special Jury Prize for Breakthrough Voice at the renowned South by Southwest (SXSW) Festival, an annual celebration of independent film and music in Austin, Texas, that was forced to cancel all its live events this year by the pandemic.

"To the family, the search hasn't come to an end and probably never will," says Shi, 27, alluding to the fact that Zhang's body, believed to be lying a few meters underground in a private landfill, is unlikely to be recovered.

"But to me, Yingying feels more like a friend than a victim, someone whose struggles, aspirations and self-doubt I share," says Shi, who has lent her own voice to the documentary by reading out excerpts from Zhang's diligently kept diary, words that anchor the movie emotionally and allow it to "forgo the whodunit trope and the lurid violence that characterizes the true crime genre", to quote one critic.

"Life is too short to be ordinary," wrote Zhang in her final diary entry on June 1, eight days before her death.

On June 29, 2017, that sentence was cited by Hou at a concert held in Zhang's name at UIUC, where the 26-year-old had been doing field research on crop photosynthesis.

Describing her venturing-out amidst a downpour during her brief stay at UIUC, another, earlier entry is drenched in loneliness. "My umbrella couldn't keep out the rain and my glasses were covered with raindrops," she wrote. "As cars were passing, I was thinking: it must be very warm inside there..."

On June 12, 2017, three days after Zhang was reported missing by Miao Guofang and Liyan, two of her fellow researchers in UIUC's Department of Natural Resources and Environmental Studies, police located security camera footage from a parking garage that showed her getting into a black Saturn Astra on the university campus.

"Now we know that Christensen, who had failed in his attempt to lure another young lady into his car that same morning, was disguising himself as a cop," Shi says. "Moreover, Yingying was already running late for an appointment she made with a rental manager. She didn't want to be late."

Shi and Sun met on a mobile chat group formed as a direct result of Zhang's going missing in mid-June, by mostly Chinese students in the Chicago-Champaign area who wanted to help. Sun, a physics student who had just discovered his interest in cinematography at the end of a four-year bachelor's program in UIUC, was instantly drawn to Shi's idea of filming the fast-unraveling event.

The concert was the first event Sun had filmed. Little did he know at the time that among those whom his camera had captured was Christensen and his girlfriend Terra Bullis, who by that time had been wearing a wire for the FBI for nearly two weeks. Christensen had just graduated with a master's degree from UIUC's physics department, the same one as Sun had been attending.

As Hou brought an aching silence to the venue with a guitar rendition of a song he wrote for Zhang, Christensen took Bullis' mobile and typed the words "It was me", followed by "she is gone ...FOREVER".

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."

On June 30, 2017, the morning after the concert, Christensen was arrested. That afternoon the police summoned the family to their office, where they were told that Zhang was believed to be dead.

"No hope was left after that day," Hou says.

But some kind of hope had to be maintained, if only to prevent the bereaved from drowning in despair. This was what Shi and Sun felt when they met the Zhang family for the first time in the university dormitory where they stayed.

The news had clearly taken its toll－the father, Zhang Ronggao, looked haggard and was for the most part silent. On the other hand, Ye Liqin, the maternal aunt, was still speaking of the possibility of "Yingying being alive". "If she's dead, she would have appeared in my dreams," she said.

In the ensuing months Shi and Sun followed the family as they searched for Zhang, inadvertently retracing her physical and emotional journey in the foreign land.

In the movie the father stood in a windswept cornfield beside the towering equipment his daughter had set up with Miao, her fellow researcher, to monitor crop growth. The slanting sunlight adds a statuesque quality to the man's solitary, middle-sized figure, reminding Shi of his own father.

In August 2018, before visiting Hou in Beijing, Shi went to Zhang's home in a small mountainous town in East China's Fujian province. Zhang's study-bedroom was on the top floor of the family's sparsely decorated and slightly rundown four-story brick house, a few steps away from the chicken coop.

The room was kept as it had always been: on a writing desk in front of the window, a lamp and a pile of award certificates, proof of Zhang's striving for excellence as a student, was collecting dust. A teenage Zhang once sat there studying into the wee hours. Once in a while she might have looked up and peered into the world map covering an entire wall on her right side.

It's a world she had set out to explore, as she journey from her native town to the bustling coastal city of Guangzhou 850 kilometers away to attend one of China's top universities, where she met Hou, her classmate. After they graduated in 2016 both were enrolled by the prestigious Peking University, Zhang in its master's program and Hou in its doctoral program. By the time Zhang left for the US, she had completed her studies at Peking University, before working briefly at the Chinese Academy of Sciences.

"Growing up, I didn't have a lot of opportunities playing with my sister－she was always up there studying," said Zhang Xinyang, Zhang Yingying's younger brother."But she never failed to turn up wherever I was beaten up or bullied by older kids.

"I'll support him as long as he agrees to work hard," wrote Zhang in her diary, faulting herself for not having cared enough for her younger brother, who quit school when he was 15.

She also harbored guilt regarding her parents.

"I called mom and dad today," she said in another diary entry. "Dad is a truck driver now, it's such hard work ... How could I think only of myself?"

Yet for Ye Lifeng, Zhang was simply the best daughter, who, with all work done, would come downstairs and snuggle right beside her in bed, moving ever so gently to avoid disturbing her.

"Yingying was the eyes and ears for her mother, who has never learned to read or write," said Wang, the family lawyer."If she had lived the life of an average girl in town she wouldn't have been able to open that window for her mother, trapped in her own shuttered existence."

Yet when Shi visited the family in August 2018 she saw only the debris of broken bowls and shattered dreams－the parents, blaming each other and themselves for encouraging their daughter to pursue a dream, fighting in front of the camera.

Reflecting on the intimacy with which she was allowed to film－the camera rolled when an inconsolable Ye lay in bed rubbing her hand against the woven straw mat she once shared with her daughter－Shi said that it took time for things to happen.

"At the very beginning, we were just two of many who had flocked to Champaign trying to get a slice of the story. But as we got to know more and more about Yingying, we decided to focus as much on how she lived as on how she died. We made sure the family understood that."

For Hou, Shi's perseverance is just as persuasive as her narrative approach."When she initially proposed the idea to me, I said no. As keen as we were to get public attention for the case, it would undoubtedly bring tremendous stress to us, especially the parents, when very often we needed to grieve in private. But she kept trying. Her passion, determination, and her experience of studying in the US alone after graduating from Peking University all reminded us of Yingying. We decided to help."

Yet most of the time Shi and Sun were with the Zhang family, they were not filming. "Let me put it this way: many times we visited them, we did so not for the purpose of filming," Sun says. "We would bring our camera and put it in a corner of the room. Other times the parents told us that they didn't want to be filmed and they still wanted to have us for dinner. We always obliged."

Asked what trait he thought Zhang had in common with her parents, Sun said,"Trusting".

He's probably right. In one of her diary entries, Zhang wrote, "I told mom that there are both Americans and Chinese here－all extremely nice."

In retrospect, some footage was eerie. In one of the earliest scenes Shi captured, in the summer of 2017, Zhang's maternal aunt, on a random search on the street, pointed to a few dumpsters not far away and said, "I really want to fumble around in that... but I'm afraid we aren't allowed to..."

During Christensen's trial between June and July last year, the Zhang family were told that "after killing Yingying Zhang, Christensen placed her bodily remains into garbage bags in the dumpster immediately outside his apartment building", to quote Steve Beckett, the family's other lawyer.

"The contents of the dumpster were taken to a private landfill. It was determined that by the time Christensen's attorneys disclosed his statement to the federal authorities (in late 2018), the content of the dumpsters that contains Yingying's remains would have been covered by at least 30 feet of fill," Beckett told media after the trial.

Yet for the family who had waited for nearly two years before flying in to attend the trial, emotional devastation was done right on the case's opening day, when the gruesome details of Zhang's death came to light.

"Although the FBI must have obtained those details through Terra's audio surveillance back in 2017, it was only toward the end of 2018 when our lawyers emailed me about what they had just been told by federal prosecutors about Yingying's death," Hou said.

Unable to find a way to break the news to Zhang's parents, Hou alerted the volunteer translators before the court opening."I told them to bypass the details," he said."But it didn't take long before Yingying's father knew－it was everywhere in the American and Chinese media."

"He became more silent from that day on," said Shi, who sat in the courtroom every day with Sun throughout the trial. Previously, the two had rented a house in Peoria, a town 90 minutes' drive from Champaign where the trial took place.

"For long hours he sat on the stoop of the family's temporary residence in Peoria, smoking nonstop. Occasionally he would let out a sigh, as if to release some of the anger and anguish that had been brooding inside his chest," Shi says.

During Bullis' court appearance, Shi gave a written note to a court worker who agreed to pass it on to her."I told her who I was and what I was doing," Shi said."She contacted me, and we became the very first to film her interview."

According to Bullis, despite speculation that the FBI may have forced or manipulated her, or have paid her, it was she who had asked, from the very beginning, "Is there a way I can help?"

Upon her own request, Bullis sat down with the Zhang family at the end of the trial. Having practiced with Shi, Bullis, who learned Chinese in high school, read a letter to Zhang's parents in Chinese.

"I drew on your love for Yingying to fight off the terror I constantly felt doing what I was doing for the FBI," said Bullis, who burst into tears with relief when Yingying's mother told her that "you are brave and just as kind as my daughter".

On June 24, 2019, the jury convicted Christensen of kidnapping resulting in the death of Zhang Yingying, a crime considered in legal realms as severe as murder.

On his drive back from Peoria to Chica-go, Wang, who had spent a thousand hours on the case, parked his car by the roadside and wept.

"Back in 2017, while the family was living in Champaign, Yingying's father took the same daily walks," said Wang, father of an adult son and daughter. "He would walk and walk until, in the far distance, a corner of the student building where Yingying once stayed appeared in sight. There he would stop and stand, sometimes for hours on end, as if waiting."

On July 18 last year after the jury failed to reach agreement over a death sentence, Judge James Shadid sentenced 30-year-old Christensen to life imprisonment without the possibility of parole. Walking out of the courtroom, Hou told the waiting media in English: "For me, the result today seems to tell me that I can kill anyone with all kinds of cruel methods and I will not need to die for it. Me, myself, will never agree with that."

Not long before the trial, it was revealed to the Zhangs that in March 2017 Christensen went to UIUC's counseling center seeking treatment for his substance abuse issues and "suicidal and homicidal" thoughts.

In the wake of that revelation, the Zhang family filed a lawsuit against the university's counselors. It was dismissed on the last day of 2019, on the grounds that the counselors had not created or increased a "specific danger" to Zhang. The suit was filed again in state court and dismissed again in June.

Wang was scathing of the university, believed to have the largest number of overseas Chinese students among all US universities.

"There are nearly 6,000 overseas Chinese students at the university at this point. Multiply that number by four, and then by the annual tuition fee the university charges them; the result is phenomenal. The Chinese student community in Champaign was shaken by Yingying's tragic death, a time for the university to show that it really cares. But on certain occasions it opted for the opposite."

Wang says the university put the family in its graduate dormitory when they arrived in the US in mid-June 2017. Yet in August they were abruptly told to leave because the university said it had leased the apartment to some graduate students."We told the university authority that since the trial would not take place in the near future, the family was probably leaving the US in a few months, and that they were more than willing to pay. But no matter how hard we pleaded, the answer was a categorical no. So the family had no choice but to move out.

"By the time the family left the US in November that year, no one had moved into that apartment."

The lawyer, who keeps in regular contact with the family these days, says that throughout there has been "one and only one wish" for the father and that's to "bring Yingying home", a wish reiterated by the man when he left the US for the second－and quite possibly the last－time in late July last year, after the trial ended.

"Information concerning the disposal of Yingying's remains was put forward as part of a plea bargain proposed by the defense in late 2018. In such cases a defendant agrees to plead guilty or make a revelation in exchange for an agreement by the prosecutor to drop one or more charges."

"Our attitude at the time was: we would not object to a deal to remove the death penalty only if Yingying's body could be discovered as a result of Christensen's disclosure. But we were told by Christensen's lawyers that 'even if he tells you everything he knows, you may or may not be able to recover anything'.

"The Zhang family's position was part of the government decision not to go along with the plea bargaining. All things discussed in this process are considered hypothetical. In other words, although I don't think Christensen had a strong incentive to lie, none of what he said about the disposal of Yingying's remains should be taken as fact."

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...