A wave of protest from Chinese bloggers has forced authorities to arrest four people and launch an investigation into 100 others after a man was beaten to death for filming a fight between villagers and local officials.

More than 50 municipal officers attacked a passer-by who paused to film them as they scuffled with rural residents over a garbage dump near Tianmen, in central Hubei province, on January 7.

The killing has provoked widespread anger in Chinese cyberspace, where bloggers have expressed outrage about the so-called urban management officers - quasi-police who are often deployed to disperse small protests or to shut down unlicensed hawkers

The villagers had been angry about the smell and pollution from rubbish being dumped near their homes, and had tried to halt a loaded truck that arrived.

Local officials called in the 'urban management' to disperse the group, and as the two sides scuffled, Wei Wenhua, the 41-year-old manager of a construction company, drove past.

When Mr Wei stopped to record the clash with his mobile phone, about two dozen of the urban management officials turned their anger on him. They tried to confiscate his phone, then beat him to the ground and kicked him to death.

Angry Tianmen residents gathered to protest and to demand an accounting for Mr Wei’s killing, but it was the outraged reaction in the blogosphere that forced authorities to fire the head of the Urban Management Bureau in Tianmen.

Scores of Chinese bloggers voiced their opposition to the officers, who have broad duties ranging from penalising illegal vendors to managing demolition projects but who also play a de facto law-enforcement role - despite this having no basis in legislation.

"This time, Hubei chengguan (the local term for the officers) have begun implementing an even more barbaric kind of power, killing anyone who might talk," one said.

Another wrote: "We must speak out loudly and ask: who gave these chengguan such absurd powers."

Zhao Mu, a well known internet journalist, posted a series of graphic images of injuries reportedly sustained by locals at the hands of 'urban management'.

He Weifang, a law professor at Peking University, said: “The dislike of these officers has multiplied over many years. Everyone can see how they deal with people so rudely, plus there is no legal foundation for their existence."

However, he said he did not expect any change to the system. “The government leans towards retaining the system in the belief it is good for stability and safety of society.”

The internet has become the principle forum for the Chinese to express themselves – albeit anonymously – in a country where the press is muzzled and those who voice open dissent face arrest and a possible prison term.

The authorities are, however, notoriously strict about the content that is able to be viewed by the country's more than 160 million internet users. The so-called 'Great Firewall of China' prevents discussion of many sensitive topics, such as the Tiananmen Square protests.

Last year, government officials also compelled Yahoo!, the American internet firm, to release to the details of two Chinese journalists who had posted an article about democratic reform, one of whom was later jailed for ten years.

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