On a Wednesday afternoon that seemed like any other, Li Lijun’s 13-year-old daughter did not return home after school. Li started to panic. “I couldn’t help thinking about all the possibilities,” she recalled. “Could she have been abducted? Is she hurt?”

Li and her family searched all the places her daughter might have gone and called everyone they could think of to ask about the girl. When there was still no sign of her after two hours, Li decided to notify the police. But in the end, the key to finding the missing girl came from an unexpected savior: a stranger on the internet.

Thousands of families across China experience the same fear each year. The previous one-child policy and a traditional preference for sons over daughters has given rise to widespread child trafficking and trading in the nation. While no official figures are available, the U.S. State Department estimated that about 20,000 children go missing in China every year. In the past, authorities have cracked down on child-trafficking networks, but tens of thousands of parents are still left hoping that their children will return home someday.

A father from Liaocheng, Shandong province, rides a motorcycle with a flag featuring his missing son’s portrait, March 25, 2015. He has visited most of China’s provinces by motorcycle in search of his son. Wei Peng/VCG

Li was lucky. After receiving word that the girl was missing, police posted her information along with a photo on Reunion, or tuanyuan, one of the online platforms that have been likened to the Amber Alert system in the U.S. The next morning, Li received a call from a stranger who had seen the post online and later spotted the girl about an hour from home. With help from the police, the runaway was safely returned to her family a few hours later.

I had been a member of the police force and thus knew there wouldn’t be enough policemen to find my child quickly. I asked friends near my home to help, but deep down I knew that the chances were slim. - Zhang Yongjiang, founder of China’s Child Safety Emergency Response

In an effort to enlist the public’s help in the search for missing children by engaging net users on social media, a policeman whose own child had gone missing set up China’s Child Safety Emergency Response (CCSER) in November 2015 in cooperation with WeChat, the nation’s most popular messaging platform with more than 846 million users. Six months later, Reunion, the first official child-search platform run by law enforcement, went online.

CCSER allows parents to post information about missing children, while police use Reunion, which issues alerts to the more than 200 million users on microblog platform Weibo. Additionally, the system sends notifications to users of online map app AutoNavi who are near the location where a missing child was last seen.

While the U.S. Amber Alert system — named after Amber Hagerman, who was abducted at age 9 in 1996 — is specifically used to help find children believed to have been kidnapped, the Chinese system assists in all missing-child cases.

“Child abduction and trafficking, and accidents like drowning and car crashes, often take place when children are not under their parents’ supervision,” Zhang Yongjiang, the founder of CCSER, said. Missing children, he added, have to be found quickly to decrease the chances of abduction or accidents.

In its first six months, Reunion sent out alerts regarding 286 missing children. A total of 260 were found. For 52, the help came too late, as they had already died — often from drowning. But clues from the system’s users helped rescue 18 children from child traffickers.

As a former policeman, Zhang knows law enforcement officials’ limitations. He has seen his fair share of terrified parents who have lost contact with their children and have no choice but to rely on sometimes-lackluster police efforts. But it was Zhang’s own experience of not being able to find his child that pushed him to establish CCSER.

A user logs into CCSER’s app in Tianjin, June 28, 2015. Jin Wen/IC

Zhang still remembers all the terrifying details of that day: He had just finished filming a TV program on child safety when he saw that he had missed 15 calls from his wife and a message in which she told him that their 2-year-old was missing. “My brain went blank the moment I saw the message,” Zhang recalled.

He called his wife and his parents, but no one answered. “I had been a member of the police force and thus knew there wouldn’t be enough policemen to find my child quickly,” he said. “I asked friends near my home to help, but deep down I knew that the chances were slim.”

Eventually, Zhang found out that his own father had picked up the child and simply forgot to inform him or his wife. What stayed with him, however, was the importance of speed in finding missing children, because child traffickers can move from one province to another in as little as a few hours. “When a policeman is dealing with 50 cases a day, he cannot spend too much time on a single case, and thus the efficiency is low,” Zhang said.

The alert system has already shown effects. The crucial next step is to promote it and to cover as many users as possible. - Zhang Zhiwei, lawyer specializing in child-abduction cases

To expedite investigation into a missing-child case, both Reunion and CCSER narrow down the search region by following the “golden three hours” rule, referring to the most crucial search period after a child goes missing. Reunion, for example, pushes alerts to people within a 100-kilometer radius in the first hour of the child’s disappearance, then a 200-kilometer radius in the second hour, gradually increasing the radius as time passes.

Lawyer Zhang Zhiwei, who specializes in child-abduction cases and is not related to Zhang Yongjiang, told Sixth Tone that advocates have long pushed for more law enforcement resources and better communication in cases involving missing children. The online platforms may well be the answer, or at least a strong start: CCSER now has 1.5 million followers, and Reunion — which also helps police departments share information about missing-child cases more efficiently and across provinces — issued more than 2.9 billion alerts to over 420 million mobile devices through AutoNavi in its first six months. An additional 14 apps, including Didi Chuxing, Alipay, Baidu, and Tencent QQ, signed on to receive Reunion alerts last month.

“The alert system has already shown effects,” Zhang Zhiwei said. “The crucial next step is to promote it and to cover as many users as possible,” he said. He also hopes that in the future, parents will be able to directly post alerts on the Reunion platform without the police as an intermediary.

A screenshot from Reunion’s official Weibo account. IC

Gaining public trust is one of the biggest challenges for nongovernmental platforms like CCSER. The system has raised some privacy concerns, and critics have accused WeChat’s parent company, Tencent, of pursuing the project for profit. Tencent told Sixth Tone that the company simply allows CSSR to use the platform. Zhang Zhiwei believes that it’s ideal for the government to lead such programs but also involve independent social organizations and enterprises.

The ultimate goal for both CCSER and Reunion is to advocate awareness of child safety — often a hot topic on social media, despite that many net users still lack basic knowledge of the issue. For example, many still mistakenly believe that police only accept missing-child cases after 24 hours have passed since the child’s disappearance, Zhang Yongjiang said. He also noted that while many people are eager to participate in online discussions, they are not as quick to take action in real life.

The fact that Chinese people tend to avoid getting involved in other families’ affairs also contributes to the problem. Volunteers at CCSER reported that they had been told to leave lost children alone because the disappearances constitute private family matters, and meddling could get CCSER into trouble. This makes it even more challenging to motivate the public to actively participate in searches, both online and offline.

“We hope that there will be more legal or compulsory measures to promote child safety,” said Zhang Yongjiang, “but more importantly, we hope that people not only care about their own children but also keep an eye out for other children.”

(Header image: A mother leads her child with a safety harness at a shopping center in Chongqing, June 1, 2014. Yu You/VCG)