A four-year federal investigation has resulted in 11 people being charged for allegedly bringing Korean women into the New York area to work as prostitutes.

The alleged brothel operators, which included a mother-and-son duo, faced money laundering and conspiracy charges, the New York Daily News reported, adding that officials accused the individuals of laundering $1.4 million over the last five years.

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The criminal complaint, unsealed Wednesday, named Manhattan businesses supposedly posing as legitimate enterprises, such as spas, but operating as brothels, according to The New York Times. It was unclear if any businesses named in the documents have been closed because of the investigation.

Some of the businesses named in the federal documents included Asian Flower, Yes Asian, Hot Lips, Asian Paradise and VIP Asian, according to the Daily News, which also stated that some of the establishments offered more expensive, condom-free “girlfriend experience” services.

Investigators also found a file containing more than 70,000 customer entries that included phone numbers and client descriptions, The New York Times added.

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Though the named businesses were independently owned, authorities indicated they shared prostitutes and customer lists, according to the Daily News, which added that most of the women, who came from South Korea, did not need permission to enter the U.S. on tourist visas.