Several employees of rural credit cooperatives in Shandong province have been placed under investigation by local police on suspicion of forging deposit vouchers amounting to 150 million yuan ($23.4 million), media reported on Monday.

An authentic voucher can be used to withdraw money.

Twenty-two depositors, 20 of them from Zhejiang province, deposited money in several cooperatives in Binzhou in 2014, according to China Central Television. But when depositors came to withdraw their money this year, they were told their vouchers were counterfeit and they couldn't get the money back.

Gu Bingwei, one of the depositors, was told in May by the Caowang branch of the Shandong Rural Credit Cooperative that the name on his voucher was one of the cooperative's employees, but the seal was not real.

Gu deposited 5 million yuan in the branch in May 2014.

Zheng Zhangcai, another depositor, was also told by the cooperative last month that his voucher was counterfeit.

"A manager of the rural credit cooperative told me the money had been transferred to a chemical factory less than three minutes after I deposited it," Zheng told CCTV.

Zheng said he came from Hangzhou, Zhejiang province, to deposit money into the bank in Binzhou because he could get an additional 5 to 6 percent interest. Zheng got the information from an agency in Zhejiang.

In China, banks are not allowed to raise interest without authorization to attract deposits, according to regulations released in September 2014 by the China Banking Regulatory Commission, the Ministry of Finance and the People's Bank of China.

A source at the Shandong cooperative, who wanted to be identified as Chen, said the case is likely the result of individual actions by employees. Chen said the provincial cooperative is waiting for the results of the investigation.

"We will do what we should do according to the court's judgment," said Chen.

A professor surnamed Man at Shandong University Law School said that whether the cooperative should be held accountable depends on details, including whether contracts were signed with the depositors and who issued the vouchers.

By Monday afternoon, details of the case had not been released as it is still under investigation, said the publicity office of Binzhou.

zhaoruixue@chinadaily.com.cn