Li Fan, a 21-year-old student, attempted suicide after posting a short message on the Chinese Twitter-like platform Weibo shortly after Valentine's Day.
"I can't go on anymore. I'll give up," he wrote.
Soon after, he lost consciousness.
He was in debt, had fought with his mother, and suffered from severe depression.
About 8,000 km from his university in Nanjing, his post was detected by a program running on a computer in Amsterdam.
He signaled the message, prompting volunteers from different parts of China to take action.
When they failed to arouse Mr. Li from afar, they reported their concerns to the local police, who finally saved him.
It may sound extraordinary, but that was just one of the many successes of the Tree Hole Rescue team.
The founder of the initiative is Huang Zhisheng, senior researcher for artificial intelligence (AI) at the Free University of Amsterdam.
Huang Zhisheng set up the tree hole rescue effort
Over the past 18 months, its program has been used by 600 volunteers across China, who in turn say they have rescued nearly 700 people.
"If you hesitate for a second, a lot of life will be lost," Huang told BBC News.
"Every week we can save about 10 people."
The first rescue operation was on April 29, 2018.
A 22-year-old college student, Tao Yue in Shandong Province, northern China, wrote on Weibo that she planned to kill herself two days later.
Peng Ling, a volunteer at the Chinese Academy of Sciences, and several others responded.
Peng told BBC News that they found a phone number for one of the students' friends through an earlier post and passed the information to college.
"I tried to text before bed and said I could pick her up," she said.
"She added me as a friend on WeChat (Chinese app) and gradually calmed down.
"Since then I've checked her to see if she's eating. We also bought her a bunch of flowers online once a week."
Following this success, the team rescued a man who had tried to jump off a bridge and rescued a woman who tried to kill herself after being sexually abused.
"The rescues need luck and experience," said Li Hong, a Beijing psychologist who has been involved for about a year.
Psychologist Li Hong says she helped rescue about 30 people
She remembered how she and her colleagues had visited eight hotels in Chengdu in order to locate a suicidal woman they knew had booked a room in the city.
"All the receptionists said they didn't know the woman," Li said.
"But one of them hesitated for a moment. We assumed it must be that hotel – and it was."
So how does the system work?
The Java-based program monitors various "tree holes" in Weibo and analyzes the messages posted there.
A "tree hole" is the Chinese name for places on the network where people post secrets for others to read.
The name is inspired by an Irish tale about a man who confided his secrets to a tree.
An example is a post by Zou Fan, a 23-year-old Chinese student who wrote a message on Weibo before killing herself in 2012.
Huang Zhisheng Software Proactively Searches Weibo Keywords
After his death, tens of thousands of other users added comments to his post, writing about their own problems, turning the original message into a "tree hole".
The AI program automatically ranks found posts from one to 10.
A number nine means there is a strong belief that a suicide attempt will be made soon. A 10 means it is probably already underway.
In such cases, volunteers try to call the police directly and / or contact the relatives and friends of the person involved.
But if the rating is less than six – meaning only negative words were detected – volunteers usually do not intervene.
One of the problems commonly encountered by staff is the belief among older relatives that depression is not a "big problem."
"I knew I had depression when I was in high school, but my mother told me it was absolutely impossible – don't think about that anymore," Li told BBC News.
The AI program also found a post from a young woman saying, "I will kill myself when the New Year arrives."
But when the volunteers contacted her mother, they said she mocked and said, "My daughter was very happy now. How dare you say she's planning suicide"?
Even after the volunteers showed evidence of their daughter's depression, the mother did not take the matter seriously.
It was only after an incident in which police had to stop the young man jumping off a roof that his mother changed her mind.
Despite his successes, Huang recognizes the limits of his project.
"Because Weibo limits the use of web crawlers, we can only collect about 3,000 entries per day," he said.
"So we can save one or two a day on average and we choose to focus on the most urgent cases."
Another issue is that some of the rescued ones require a long term commitment.
Sometimes volunteers find themselves checking rescued contacts over weeks and months.
"Most of my life is now occupied by these rescued people," Li said.
"Sometimes I get very tired."
She said she is currently in contact with eight people who have been rescued.
"I have to answer them right after they send me a message," she said.
Some team members also try to provide offline help.
For example, an AI teacher is said to have found data labeling work for a person found with a social anxiety disorder.
There is also the question that suicidal thoughts may return.
Peng gave the example of a young woman who "looked better every day" after being rescued but then killed herself.
"She was talking to me about getting a new photographic portrait on Friday," Peng said, adding that two days later the woman was dead.
"It's a big shock to me that a person you have been in contact with for a long time is suddenly not there."
On the other hand, Li remains healthy and now works in a hotel.
"I like this job because I can communicate with many different people," he said.
He added that he was very fond of the rescue team's efforts and, ultimately, it was up to each individual to come up with a long-term solution.
"The joys and sorrows of different people are not completely interconnected," he said.
"You must redeem yourself."
Illustration drawn by Davies Surya
At the request of respondents, the names of the rescued persons involved were changed.
If you have been affected by self-mutilation, mental health problems or emotional suffering, help and support are available via BBC line of action.