Fan Yafeng, a respected legal advocate, received a call inviting him to the local police station for a chat.
When he got there, a hood was thrown over his head. He was shoved into a car and taken to an undisclosed place. Fan was forced to sit motionless for more than 10 hours and was beaten if he moved.
He was tortured for nine days and threatened with 20 years in prison for allegedly engaging in illegal business practices and subversion.
Released almost two weeks later, the normally fearless legal expert was a broken man. He refused to go public with what had happened to him and asked friends not to contact him.
Fellow lawyers thought this reticence was a mistake.
'People were afraid the methods used against him would be used against other lawyers,' one colleague said.
And that is exactly what has happened to numerous rights lawyers and activists in the months since.
One expert on human rights said the frightened lawyer was No 1 on a list of some 20 lawyers and countless activists who were targeted. Over the following months, these lawyers were picked off, one after another, each in turn facing a similar cycle of abduction, detention, beatings and, sometimes, torture.
The campaign has given rise to a new vocabulary of fear, including phrases such as 'to be disappeared' and 'to be black-hooded.'
Each victim emerged from captivity insisting on remaining silent.
'I'm sorry, but I can't chat with you for the time being,' one normally outspoken dissident told this reporter over a Skype exchange soon after his release from detention. 'I have to keep a low profile for a while.'
In one surprisingly frank and desperate tweet on the Twitter website, lawyer Li Xiongbing wrote after being detained for two days: 'I'm really very afraid right now; please don't try to reach me, OK?'
He said he was returning to his hometown to be with his parents and to seek psychological help.
For years, rights lawyers and dissidents have played a game of cat and mouse with the mainland authorities, refusing to buckle in the face of harassment, licence revocations, detentions, beatings and, sometimes, brutal torture and imprisonment.
But over the past six months, the feared guobao, or domestic security apparatus, which monitors the activities of activists, has adopted unknown new tactics that have frightened its targets into silence.
'The methods they're using are different now,' a Beijing lawyer said. 'Now no one is willing to talk. When you call them, they won't even answer the phone. They obviously received a serious warning. The methods being used have exceeded their ability to withstand the pressure.'
The lawyer said the level of fear has been raised, 'sending a message of fright to the entire society.'
Apart from going silent, some lawyers have started to turn down cases.
'These lawyers used to take controversial cases,' said one US-based lawyer, 'but since the crackdown, it has been noted by one of the lawyers that it is difficult for people to find lawyers for sensitive cases, especially religious cases, such as those involving the Falun Gong.'
Many of the lawyers and activists have been illegally detained and held for excessive periods in violation of Chinese laws. In some instances, people have been abducted off the streets, with a black hood thrown over their heads by non-uniformed security officers.
The victims of 'black-hooding' are often illegally held in unknown locations, incommunicado for periods ranging from days to months in what some call a 'black box'. Sometimes the abductions are carried out by thugs hired by the police to intimidate the targets.
'The most worrisome thing is that what we know the least about is what measures they're using to keep people silent upon their release,' said Jerome Cohen, professor and co-director of the US-Asia Law Institute at New York University's school of law and adjunct senior fellow for Asia at the Council on Foreign Relations.
'Many of these guys are tough. What could be so effective? Apparently, there are new measures that are making them less willing to be contacted upon their release.
'What could you do to these people to make them unusually silent when they should have expressed outrage?'
Some details of the treatment may be known to fellow lawyers, but except for a handful of cases, those released have vehemently refused to go public with what happened to them, apparently under threat from the authorities, who warned them not to speak.
Even when the details are known, experts and journalists have been reluctant to speak publicly about them for fear the release of the information could result in official retaliation.
In some cases, however, it is believed the targets were allowed to tell fellow lawyers of their experience, using a strategy called 'killing a chicken to scare the monkeys'.
'We felt, at the same time, they wanted him to speak out in order to raise the level of terror,' the Beijing lawyer quoted earlier said of a colleague who had been detained.
'They wanted to use him to threaten everyone else.'
The human rights scholar agreed, saying: 'This is a perfect way of spreading terror.'
Cohen feared that the methods used by police were 'more sinister' than torture methods known to have been used before. 'Is there something more and more unnerving?'
According to some reports, threats have been made regarding the family members of the people targeted in the campaign.
In one case, police summoned the wife and small child of a lawyer to the police station, where they were intimidated. Police told the wife: 'We can deal with you in the same way we dealt with your husband.'
Another lawyer was repeatedly warned: 'You should think about your family.'
'This is the revival of the old custom of family retribution - collective criminal punishment,' Cohen said, referring to a tradition from imperial days, when the relatives of criminals were also punished.
'I worry about threats to family members. How can you risk your family for human rights?'
It seems certain that plain old torture has been used in many cases.
Jin Guanghong, a rights lawyer, was forcibly medicated after going on a hunger strike. Sources said he could no longer remember clearly what happened when he was in captivity.
Tang Jingling, a Guangzhou lawyer who also was forcibly medicated, seemed unable to recognise people since his release, other sources said.
Many of those detained were apparently forced to sign confessions, letters of repentance and guarantees they would not engage in rights work any more or have contact with foreign friends, the media or people within their circles. And if they met anyone, they were required to report it to the police.
The techniques used to secure compliance appear to have been consistent.
'They were made to confess, and then they made the person take the transcript and read it out to the camera,' a source said.
'There were varying numbers of promises and commitments that had to be made, but all of the lawyers who were detained could only be taken back if they signed guarantee promises.'
Detainees were asked about a few general topics: contact with foreigners, whom the police see as anti-Chinese; oppositionists, lawyers and other activists who challenge the party; and the 'jasmine revolution'.
According to a translation by Global Views, Shanghai-based rights lawyer Li Tiantian confided on her blog after her release that she had provided information about 30 people she knew. She said she 'wrote down all the facts that I know.'
The signing of such documents, even under duress, appears to be having a huge impact on these lawyers and dissidents.
'Signing a letter of repentance or a guarantee means you have been broken in the eyes of your friends and perhaps in your own eyes,' the human rights scholar said.
She said it was still remarkable, however, that the detainees had been so effectively silenced as a result.
'It's the shame,' she suggested. 'Chinese friends themselves comment that China has a culture of heroes. You have to be absolutely able to withstand everything. Even if they understand that these expectations are exaggerated, they will still feel under pressure to live up to them.
'In addition, some have obviously been threatened with criminal prosecution, so any documents they have been forced to sign could later be used as evidence against them.
'There are also recordings of people reading their own documents, and so there is a risk of further humiliation if these are ever released.'
Li, who was detained for three months, wrote on her blog following her release that her boyfriend and his siblings had been visited by the police several times and were asked to break ties with her.
The boyfriend and his family were forced to watch a video that showed Li walking into hotels with a string of other men, implying she was having sex with them.
China watchers are scratching their heads over this spate of arrests, which some say is the worst crackdown since the 1989 bloody suppression of student demonstrators. The detentions began to intensify at the end of last year and picked up steam in February after attempts to launch a 'jasmine revolution' in China.
'These people are the only source of legal resistance,' Cohen said. 'It's a small group, and if you can disable them, people can't defend their rights.'
One lawyer who was detained for an extended period, during which he was not allowed to sleep for days at a time, was beaten for two days and forced to zuoban, or sit motionless, for hours. Several security officers took turns interrogating him, asking him the same hundreds of questions over and over again.
In the end, he, too, caved in. When he was released, he was much thinner, people who saw him said.
'They say the draft letters of repentance that he signed reached this high,' said the Beijing lawyer, holding his hand out about 30cm over a coffee table. Another source said the detained lawyer signed no fewer than eight guarantees.
Tang Jitian, who was held for 21 days, was diagnosed with tuberculosis upon his release. It is said his body was weakened by his being given little food, limited clothing to wear and being forced to withstand strong air conditioning during his detention.
The human rights scholar said the lawyers who were detained in recent months spent much less time in captivity, 'having made up their mind that they would co-operate sooner rather than later.'
'One interpretation is that the intimidation has already worked,' the US-based lawyer said. 'There's no need to spend months to break the lawyers.'
Li, who wrote she was in a hospital for three months, an obvious reference to her detention, published a parable on her blog one day after being released on May 24.
She described a hornet that was worried a little bird might disturb its nest.
According to one translation: 'The hornet grabbed the little bird and began stinging it frenziedly. Unable to bear the hornet's stings and thinking there was no point suffering this ordeal, the bird realised that no one would gain anything and there was no way to change the hornet's ways. So the bird knelt down to the hornet and kowtowed in order to extricate itself.
'The hornet, knowing that the force of justice was on the rise in the animal world, didn't dare do anything rash to the bird and came up with a plan that would satisfy everyone. It agreed to release the little bird, but only if the bird promised: 1) not to speak of the past few months; 2) not to damage the hornet's reputation; and 3) not to urge other animals to stir up the hornet's nest. Finally, the bird was freed.' v Li concluded by saying she would not stick her head out again for a while: 'Under the present circumstances, there's nothing wrong with being a tortoise hiding its head. At least they live to an old age.'
But, as if she could not bow down, Li began tweeting the very next day, describing the details of her interrogations. She described how national security officers used information they had gathered about her sexual relationships with other men in an attempt to intimidate her and, by extension, other lawyers.
The blog was soon shut down.
The human rights scholar said the silence of the lawyers might be a temporary thing.
She said that as people were released, they had slowly been getting in touch with one another, often surreptitiously, such as in 'chance' brief encounters in a produce market or a store.
Cohen said he believed there were discussions going on within the top leadership about the campaign.
'How can you expect unanimity on a question like this?' he said.
The American expert on China's legal system said the campaign of terror could only come to an end 'if the top leadership decides to stop it.'
The Beijing lawyer, however, was doubtful things would return to normal soon.
'Some people are optimistic things will change in a few years,' he said. 'I don't think so.
'The measures have been very effective. It will go on for a while.'
Jin Guanghong, lawyer
Forcibly medicated; tied up and beaten; given injections. Can't remember much. Disappeared on April 8 or 9 and returned home on April 19.
Tang Jingling, lawyer
Forcibly medicated; tied up and beaten; given injections. Can't remember much. Put under residential surveillance for 'inciting subversion of state power' but being held outside his residence.
Jiang Tianyong, lawyer
Detained for two months, from February 19 to April 19. Beaten for two days for refusing to collaborate.
Teng Biao, lawyer
Detained for about 68 days.
Tang Jitian, lawyer
Detained from Feb 16 to March 4.
Li Fangping, lawyer
Detained from April 29 to May 4.
Li Xiongbing, lawyer
Detained for two days, May 4-6.
Xu Zhiyong, lawyer
Detained for one day.
Liu Shihui, lawyer
Missing since Feb 20. Earlier, he was brutally beaten by a group of unidentified individuals at a bus stop.
Li Tiantian, lawyer
Disappeared on Feb 19 and reappeared on May 24.
Liu Xiaoyuan, lawyer
Detained for six days.
Ni Yulan, lawyer, and husband Dong Jiqin
Believed charged with 'creating a disturbance', Ni and her husband were taken into detention on April 17. She is thought in poor health.
Fang Yafeng, legal scholar
Taken to a secret location on December 9 and tortured for several days.
Ai Weiwei, artist
Detained on April 3. Ai has not yet been formally arrested or indicted.
Ran Yunfei, writer and blogger
Detained on February 20. Formally arrested on March 25 for 'inciting subversion of state power'.
Wang Lihong, citizen journalist
Taken on March 21 and formally arrested on April 20, and charged with 'assembling a crowd to disrupt social order'. In poor health.
Yu Jie, writer
Believed to have been seriously tortured.