The director of a detention house who took two prisoners out to buy sex is now a prisoner himself.

The director, surnamed Hua, was charged with abusing the power of his post and sentenced to a year and a half in prison.

"Whether Hua himself bought sex or not is not important, as taking two detainees out for entertainment was enough to support the accusation," said Jin Li'an, the head of the research office for the Jianye district court in Nanjing, capital of Jiangsu province.

The two detainees, surnamed Huang and Guo, were the heads of local gangs and knew Hua well.

In September last year, Huang and Guo, detained in the Jiangdu detention house, asked Hua to bring them their "girlfriends".

One night, Hua, working the night shift, secretly took the women he contacted to an interrogation room to meet the two detainees.

Hua kept watch and later took the two women out of the detention house.

On Oct 3, Hua let another two women into the detention house, where Huang and Guo allegedly had sex with them.

The following day, Hua reportedly drove Huang and Guo to Jiangsu's city of Yangzhou, about 20 km away, to "relax".

They spent the whole night in a club and a bath center, before heading back to the detention house about 4 am the next day.

According to the court, Hua said the two prostitutes met them that night, but he himself did not.

Hua also said the two paid for everything.

Hua thought his actions were being kept secret until someone, reportedly an adversary of the two detainees, sent a letter to the local procuratorate.

Hua was later removed from his post and arrested.

There is no evidence of Hua receiving bribes from his two friends other than a pack of cigarettes.

"Hua's case is really unusual," Jin said.

"However, it is alarming how much he could cross the line as an official and none of his colleagues ever reprimanded him or accused him of wrongdoing."