Since the campaign began this winter, experts and citizens have questioned whether it would have any lasting results or whether it was a mere show to stem increasing disenchantment with the ruling Communist party. So far, most reports of corruption have originated from online whistleblowers like Mr Zhu, who post their findings on China's Twitter-like microblogs, Weibo. Some bloggers had hoped the new anti-corruption drive would help them avoid the harsh government reprisals they have experienced in the past. But many are increasingly quoting an ancient saying once used to describe the execution of criminals and now used to warn of the party's long, unforgiving memory: "Wait to settle your score after the autumn harvest." If local authorities are allowed to punish whistleblowers, experts warn, the anti-corruption campaign will lose what little momentum it has gained in the past two months. And of all the scandals exposed since the campaign began in November, Mr Zhu's was the most salacious and high-profile.

Mr Zhu, a self-described "independent investigative journalist" based in Beijing, released a graphic video, filmed about five years ago, showing a local party boss in the metropolis of Chongqing having sex with his 18-year-old mistress. The video of Lei Zhengfu, 57, soon went viral as a symbol of party corruption, and Mr Lei was fired within days. But details of the case were kept under wraps until Friday when government-run media announced the removal of 10 more party officials. According to reports in Chinese media, including the state-run CCTV, young women, who secretly taped their trysts, were sent by property developers in a plot to extort construction contracts from Chongqing officials. In the wake of the scandal, Mr Zhu remained relatively unscathed. He said he received two death threats from people he believed were associates of Mr Lei, but was left alone by authorities. In a November interview, he said he had five more sex tapes depicting other officials with young women that he was waiting to release.

Initially, Mr Zhu said his experience had given him some hope for reform. "In the past I've encountered a lot of threats, censorship and even kidnapping, but this time, my website wasn't shut down. There was no blocking or attack," he said. "I think maybe the sky really is changing." But by Sunday night, he was reevaluating his position. Police had searched for him at another home where he occasionally stayed, frightening family members. And now, they were just outside his door. The men claimed to have come from a local Beijing security station, but Mr Zhu suspected that they had actually come from Chongqing and that their true intent was to take him away and recover the five additional sex tapes he had threatened to release. Just recently, a source told him Chongqing authorities had destroyed all other recordings related to the extortion case in an attempted cover-up, leaving only the video Mr Zhu had already made public.

Upon hearing that, Mr Zhu said he transferred the unreleased videos to friends in the United States, which he called "the safest place in the world." The videos, he noted, included officials who have not yet been punished or fired. "If something bad happens to me, I hope my friends will release those videos immediately," he said. Subsequent calls to Mr Zhu on Sunday night went unanswered, but he posted a message online saying that police had agreed to meet him and his lawyer at the station Monday morning and that they had left minders at his home. In later posts, media professor Zhan Jiang said he had visited Mr Zhu at his home, and lawyer Wang Peng said he also visited Mr Zhu and noted a police car with Beijing plates stationed outside. "If tomorrow I still end up being taken away by Chongqing policemen," Mr Zhu said in his last message of the night, "I hope all of you will continue supporting me."

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