Chinese officials arrested on corruption charges have alleged they were tortured into confessing to crimes they did not commit.
A catalogue of horrors said to have been perpetrated by their state torturers included being forced to eat faeces and hallucinogenic drugs, water torture and savage beatings.
"My time in shuanggui (Communist party detention) was tragic and brutal. It was a living hell," Zhou Wangyan, land bureau director for the city of Liling, told AP.
"Those 184 days and five hours were not a life lived by a human. It was worse than being a pig or a dog."
Zhou said he was subjected to torture for 184 days before he confessed to graft as the Communist party regime heightens its fight against corruption under the leadership of premier Xi Jinping.
Zhou was detained for six months at the notorious Qiaotoubao centre of anti-corruption where he had his thigh bone snapped by interrogators. He still walks on crutches 18 months later.
Before his release in January 2013, Zhou gave what he said was a false confession to stop the torture. He signed a confession document that stated that he had received £3,900 (40,000 yuan) in bribes and wrote a resignation letter to that effect.
During his torture he said he was pinned down and force-fed excrement with a spoon. The interrogators called it "American Western Feast" and "Eight Treasures Porridge".
He was punched, dragged by his hair and forced to smoke 10 cigarettes at once. Interrogators broke four of Zhou's teeth by hitting him with a shoe and dunked his head into water until he believed he was drowning.
Zhou's testament was corroborated by medical records, police statements and interviews with his family.
Three others who detailed their experience provided other horrifying first-hand accounts of torture at the hands of Chinese interrogators.
Wang Qiuping, an official in Ningyuan, was forced to stand and kneel for hours on end during his year in detention while Wang's deputy, Xiao Yifei, was beaten by a man known as "Tang the Butcher" and hooded for an entire month.
Fan Qiqing, a contractor in Ningyuan, alleged that he was lashed and forced to ingest hallucinogenic drugs.
A local official said that an investigation into three corrupt officials had found no involvement in torture.
Analysts have estimated that several thousand people are detained every year under a secret internal system that is not linked to the state justice structure.
The alleged torture methods have been used on normal Chinese citizens, such as activists, as well as supposedly corrupt officials.
China has been widely criticised for its human rights record and recently refuted a UN report linking its role in North Korea's human rights abuses.