Fei Fei, a netizen in Hubei province, received a call during the National Day holiday from someone claiming to be a policeman. The caller said he was involved in a money laundering case and that Fei's credit card had been found.

The caller, who identified himself as Wang Hao, told Fei that the case had been cracked on July 15. The suspect had made use of her credit card to launder money.

He then asked whether Fei had lost her card.

Fei replied that her card was not lost, and she didn't know the suspect.

The "policeman" than asked her to provide her identity card number for "confirmation". She refused, using the excuse that she could not remember it.

In fact, she realized the call was a fraud and had enough security awareness that she knew not to disclose any personal information. What's more, she recorded the conversation and provided it to provincial public security officials.

The authorities exposed the recording later, along with another two similar fraudulent calls, on their micro blog on Sina Weibo, aiming to keep more residents from being cheated and unmasking swindlers' tricks.

The police called the recordings the "Bad Voice of China", a word play on Voice of China, a popular TV talent show that concluded earlier this month.

The police posted an e-mail address on the micro blog and called for residents to collect more recordings of such frauds. They promised to expose the crooks.

"Publishing the 'Bad Voice' can vividly show cheaters' tricks, enhancing people's ability to identify, resist and prevent more fraud calls," a publicity spokesman quoted Wu Chunli as saying.

Wu, who heads public security departments specializing in the handling of key criminal cases, told the media that officials hope to crack down on fraud more effectively by exposing swindlers' voices via micro blogs and WeChat, a hot instant messaging tool popular throughout the country.

She said that they have established a group for cooperating with telecom and financial authorities to improve the accuracy and efficiency of crackdowns. She said people should not believe the latest frauds, which often claim a person has won a prize, benefited from a stock investment or that a relative needs to borrow some money.

caoyin@chinadaily.com.cn