MasterCard and American Express have recently announced that they will be barring the use of their credit cards to pay for sex ads on Backpage.com. Visa also banned its service on the site, which is allegedly being used for sex traffickers.

According to Cook County Sheriff Thomas Dart, the ads for escorts on the site are part of a group of sex-trafficking industry players that prey on the young and vulnerable. The site offers forums to find roommates and sell goods, like other classified advertising sites like Craigslist, but its primary revenue stream is through its adult page, added Dart.

Bitcoin Payments Accepted?

With that, the sheriff asked credit card companies to remove their association from the services offered in Backpage.com’s adult section. “Visa’s rules prohibit our network from being used for illegal activity,” said Visa spokesman John Earnhardt in a statement on Wednesday. “Visa has a long history of working with law enforcement to safeguard the integrity of the payment system and we will continue to do so.”

Spokespersons for both MasterCard and American Express have also confirmed their discontinuation of services related to the website. However, bitcoin payments are still accepted by the website, which Dart says would make it more difficult to catch perpetrators.

Bitcoin payments are typically anonymous, as there is no record of the counterparties involved in the transactions. The transactions are simply recorded on a public ledger called blockchain, which is updated and verified by a network of computers solving complex algorithms.

With that, authorities will be unable to track buyers or sellers on these sex ads, although Cook County Sheriff’s police have made more than 800 arrests since 2009 stemming from Backpage ads. “We have no naive notion that we’ll end prostitution, end trafficking, end exploitation of children,” Dart said. “What we’ve wanted all along is to make it more difficult and make (traffickers) easier to catch.”