Extracts from a government manual on how to beat troublemakers without leaving physical evidence have emerged in China.

Details from the official publication were posted on the internet by a civil servant and published in one of the country’s most daring newspapers.

One of the most controversial passages reads: “In dealing with the subject, take care to leave no blood on the face, no wounds on the body, and no witnesses in the vicinity.”

The guide appears to be aimed at local government enforcers known as chengguan, who are often involved in public confrontations in their main role of removing unlicensed street vendors and checking permits. They play a de facto law enforcement role and have attracted criticism for their heavy-handed and frequently violent methods.

A local government official told the Southern Metropolis Daily newspaper that he had posted the extracts online after buying a copy on sale openly at a government bookshop. Some of the contents, such as avoiding leaving marks on a subject, were “inappropriate”, he said. “I was shocked . . . these things used to be spread by word of mouth, but now they’re out in the open. Things like how to protect yourself and how to hit people.”

Any doubts as to whether the contents of the handbook — The Practice of City Administrator Law Enforcement — were authentic were laid to rest when the Southern Metropolis Daily obtained confirmation from the Government in Beijing. It quoted an official of the Beijing Municipal Bureau of City Administration and Law Enforcement as saying that his office was the author of the book.

He voiced surprise that portions had been posted online, asking: “Who put it up on the net? How did internal material come to be discussed outside?”

Among the most controversial recent incidents involving chengguan occurred early last year when a group of officers attacked a passer-by who had paused to film them on his mobile phone as they scuffled with rural residents protesting against a rubbish dump in their neighbourhood.

The officers turned on Wei Wenhua, 41, the manager of a construction company, and beat and kicked him to death. Four men were later jailed for terms of between three and six years for his killing.

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