The authorities in Hunan Province are investigating a case in which prison officials are alleged to have helped inmates gamble and plan to strengthen supervision over prison management.

The Hunan Prison Administration Bureau under the Justice Department announced that they have set up a group to investigate guards who reportedly brought playing cards and cash for prisoners to gamble with into Yanbei Prison, news site thepaper.cn reported on Sunday.

Zou Baosheng, who was released from Yanbei Prison in Hengyang three months ago, was quoted by thepaper.cn as saying that he lost 90,000 yuan ($13,743) while gambling in the prison.

Zou said that prisoners from the second section of Yanbei Prison began to gather in October 2014, and play cards with a 100 yuan stake.

Zou said that the cards and money were brought in by prison officers since prisoners are not allowed to have cash, and they could get officers to withdraw cash for them by giving them 500 yuan for each 10,000 yuan.

Huang Xiongmao, who is still serving a sentence in Yanbei and participated in the gambling, provided materials to thepaper.cn, adding that officers in the prison told him to stop revealing the case.

The deputy director of the disciplinary committee of Yanbei Prison, surnamed Chen was quoted as saying that the prison has conducted an investigation into the case and there is no evidence that proves that the cards and money were brought in by officers.

However a notice acquired by thepaper.cn showed that several prison officers received punishments after it was found they were involved in gambling in September 2015.