China has sacked 13 officials for publishing fake photographs of a South China tiger in a scandal that has sparked a passionate online debate about conservation and local government corruption.

Zhou Zhenglong, 54, the farmer accused of fabricating the pictures, has also been detained on suspicion of fraud, according to the Xinhua news agency. After identifying plants in the photos, a police investigation concluded that if the tiger had been real it would have been only 27 centimetres long, local media reported.

Forestry officials in Zhenping county, in Shaanxi province, published the photos in October, saying that they proved the existence of the tiger – not seen in the wild since 1964. They paid Mr Zhou a reward of 20,000 yuan (£1,500), banned hunting in the region and launched a massive search for the big cat – one of the ten most endangered animals on the planet.

The provincial government has now admitted that the photographs were fake, telling a news conference yesterday that images had been borrowed from older pictures. Bao Shaokang, spokesman for Shaanxi’s Public Security Bureau, said that Mr Zhou had admitted using an old picture of a tiger placed in foliage in the mountains.

Mr Bao said that the farmer had heard there would be a one million yuan (£73,000) reward for proving the existence of a South China tiger in the wild. Local media said that the officials involved planned to use the photos to attract investment in a South China tiger reserve that they hoped would become a big tourist site.

The scandal has also sparked an unusually national debate, driven by the outspoken online community, about corruption in local government and China’s patchy conservation record. Hu Jintao, President of China and Communist Party chief, was even questioned about it when he took part in an online chat with the public for the first time ten days ago. By yesterday afternoon there were more than 400,000 comments about the arrests on the sina.com site alone. “The credibility of our Government is really worrying!” wrote one. Another wrote: “When a local government behaves like this, people will definitely ask it to collapse as soon as possible, and capable people should take over.”

In another example of public frustration with local officials, thousands of villagers rioted on Saturday in protest at the handling of a student’s death in the province of Guizhou. The protesters set fire to a police station, government offices and cars in Wengan county after an official ruling that a 15-year-old girl whose body was found in a river had committed suicide. Internet postings said that she had been raped and killed nine days ago and that the police were trying to cover up the crime to protect the main suspect, who was the son of the vice-head of Wengan county.

Pictures that lied

— In 2005 British tabloids ran photographs of a black panther roaming in South Wales. The British Big Cats Society proved the animal was a life-sized cuddly toy

— A photograph of the Loch Ness Monster taken in 1934 was created by using a toy submarine with a serpent's head model attached

— In the Cottingley Fairies Hoax, Elsie Wright and Frances Griffiths took photographs of fairies deemed authentic by Sir Arthur Conan Doyle. Sixty years later the girls admitted that the fairies were paper cutouts

— A computer-generated image from the film Armageddon was circulated on the internet as an actual satellite image of the Columbia shuttle disaster

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