Two men involved in a black-money scam were captured on Nov 7 in a police set-up, Beijing authorities said yesterday.

According to a press release from the exit and entry administration of the Beijing municipal public security bureau, two African men were arrested at a hotel near Tuanjiehu, Chaoyang district.

Police said the arrest happened during a sting operation, adding they also found black paper and counterfeit dollars on the scene.

A black-money scam occurs when a con artist procures money from a victim by duping them into believing that paper currency had been dyed black to evade customs.

Through an expensive chemical wash the black paper is apparently returned to genuine money status.

The victim at the set-up, identified only as Wang, told police she had met an African man named Carl online in early August. Carl claimed his father worked for the office of the United Nations High Commission for Refugees (UNHCR).

Wang and Carl held online chats between August and September.

On Oct 20, Wang met Carl and a man named Polo, who claimed to Carl's friend, in a hotel near Xiaohongmen, Chaoyang district.

According to Wang, Carl said he had received a pension payment to his father from UNHCR. The money had been temporarily stored in an embassy in Beijing.

Carl said the money had been turned black to evade customs and could only be cleaned with special chemicals that Polo was in possession of.

Wang says she was asked to pay 6,000 yuan first to get the money out of the embassy.

The pair met a second time in the same hotel on Oct 26. This time Wang gave 110,000 yuan to Carl in exchange for an unspecified amount of dollars, who then pretended to turn one of the black notes into US currency.

The victim said Carl requested more money to buy chemicals from Polo to complete the transformation.

The following day, Wang gave Carl another 15,000 yuan and set a date for her to pay another 60,000 yuan in early November.

Wang called Chaoyang district police a few days later after discovering the con. She then agreed to act as bait in a police sting operation.

Beijing police yesterday warned local residents not to be fooled by black-money scams.

"People should use their common sense," said Li Song, press officer of the Beijing police force.

"Residents should tell the police immediately if it happens to them," he said.

The police said they are gathering evidence to present to a possible court case against the two men.