“THE people’s police love the people, the people love the people’s police” is a well-known ditty that officials claim is cherished and accurate. Earlier this month, however, Global Times, a newspaper in Beijing, said that police were struggling to convince the public that they had acted properly in the case of a 29-year-old man who died in the capital while in their custody. Disdain for and distrust of the police is, in fact, widespread. But it is rare for an organ so closely linked to the Communist Party to admit that officers have a credibility problem.

Police said they had detained the man, Lei Yang, on May 7th during a raid on a brothel; that he had resisted arrest and died of a heart attack. His family and friends used social media to challenge this account. They said that Mr Lei was fit and had no record of heart trouble; that he was on his way to the airport to pick up relatives when he disappeared; and that timings and other details given by the police were implausible. These counterclaims created a firestorm online, and even in state-linked media.

The case is the latest illustration of how social media—despite huge efforts by the government to block access to online information that it considers sensitive—play an important role in China’s public and political life. Censors tried hard to delete posts critical of the police handling of Mr Lei’s case. But it proved impossible to keep up with the deluge.

Such efforts by the censors are relatively easy for internet users to detect. More difficult to monitor are the government’s attempts to influence online discussion by intervening surreptitiously with posts and comments they disguise to look like they come from the public. A new study published by Harvard University offers a rare analysis of how this works. On the basis of a leaked e-mail archive from a local government’s propaganda office, the authors conclude that 488m such bogus posts appear each year, about one out of every 178 of the messages that are posted each year on commercial sites.

Contrary to popular belief, those involved in this effort avoid arguing with sceptics of the government. Instead, the scholars write, they try to distract the public and change the subject. Most of their posts gush with praise for China, the party or other symbols of the regime (such as the much-loved police).

The authors describe this as a “massive secretive operation”. But its existence has long been suspected. The government’s online cheerleaders are commonly disparaged as belonging to the “50-Cent Party”, a reference to the amount, equivalent to eight American cents, that they are rumoured to receive for each pro-government post. The scholars believe, though, that most 50-centers are government or party officials, and that they are paid nothing extra for their online scribblings.

Their posts were clearly of little use during another recent scandal that came to light thanks to a furore on social media. It involved the death of a student who spent vast sums of borrowed money for an ineffective course of cancer treatment at an army hospital. He had learned about it from Baidu, China’s largest search engine, which did not make clear that advertising payments skewed its search results.

In an e-mail reportedly sent to his staff Baidu’s CEO, Robin Li, wrote that as a result of the scandal, Baidu faced a crisis in public trust. “Baidu could go bankrupt in just 30 days if we lose our users’ support,” he wrote. The episode was a huge embarrassment to the party too. But if its leaders have the same worries as Mr Li, they have yet to become public.