Authorities in Thailand arrested more than a dozen people who they believed were behind the online gambling websites that generated THB100 million (US$2.85 million) monthly, local media reported.

Thai officials made a sweep of 18 locations across Bangkok on Wednesday, which led to the arrest of the 16 individuals believed to be the clerical staffs in call centers taking bets and handling accounts, according to a Thaivisa News report.

Officials said the arrested—all of them Thai nationals—will face charges of money laundering and advertising gambling, which is punishable by up to two years in prison and fines of THB5,000.

Some 50 computers, communication equipment, bank books and accounts were seized from the offices. Anti-Money Laundering Office (AMLO) chief Pol Colonel Sihanart Prayoonrat told The Nation that they have already frozen a total of THB10 million in 38 bank accounts that were allegedly held by members of the gambling network.