Police raided 13 premises suspected of running online gambling in Bangkok and Chiang Rai on Tuesday, and impounded assets worth about 1 billion baht for examination.
The raids were launched to bring down a gambling website called SCG9, said Pol Gen Damrongsak Kittiprapas, the national police chief.
The website had been operating for three years, with about 3 billion baht in circulation, he said.
The raided premises included five condominiums on Ratchadaphisek Road in Thon Buri district of Bangkok.
In one of the condos, police arrested a man identified only as Atthaset who also had ketamine in possession. Police impounded 2.65 million baht in cash, a Toyota Alphard, a Porsche Cayenne, a Porsche Carrera, and 39 luxury watches including Richard Mille, Audemars Piguet and Rolex.
Police also seized 18 land title deeds, 65 bank books, 25 brand-name bags, five luxury belts, 59 Bearbrick dolls, ornaments and notebook computers.
Also raided were three commercial buildings on Charan Sanitwong 68 Road in Bang Phlat district, Bangkok.
There officials impounded a Mercedes-Benz car, a BMW car, 46 bank books, 140,000 baht in cash, copies of six land title deeds, fund, debenture and share certificates, 14 cashier cheques, 23 luxury bags and three luxury watches.
Police arrested another man identified only as Boonprasit at an apartment in Phasi Charoen district, Bangkok, for allegedly withdrawing money for the gambling network and laundering them.
Pol Gen Damrongsak said the suspect withdrew money from the bank accounts of people hired to open them for the gang.
In Mae Sai district of Chiang Rai, police arrested three more suspects identified only as Kittikorn, Rung-arun and Thongthai for opening bank accounts for the gang.
Deputy national police chief Pol Gen Torsak Sukwimol said the raids were aimed at tackling the gambling website, www.scg9.club, which hosted many kinds of gambling including World Cup gambling.
The website had many members. The host offered bank deposit and withdrawal services with commercial banks and advertised gambling services on social media and other online channels.
Police found financial transactions worth more than 3 billion baht linked to the online gambling network. Detectives intended to later reach the real owners of the illicit business, Pol Gen Torsak said.
He also said that police estimated the value of seized land title deeds at about 600 million baht and luxury watches at 100 million baht including a Richard Mille watch worth 25 million baht.
Whenever the gambling network generated revenues, part of the money was invested in stocks and the investment was estimated altogether at 160 million baht, Pol Gen Torsak said.