Prosecutors plan to press money laundering charges against Chinese businessman and suspected crime boss Chaiyanat "Tuhao" Kornchayanant by the end of the week, according to the Office of the Attorney General (OAG).
Kulthanit Mongkolsawat, chief of OAG's Investigation Office, said investigators have sufficient evidence to back the money laundering allegations made against Mr Chaiyanat.
Mr Chaiyanat is under investigation after he was found to be a key figure in a Chinese criminal syndicate which runs a number of illegal businesses in Thailand. Police believe the criminal syndicate is involved in the illicit drug trade, after narcotics were found in a venue that was linked to Mr Chaiyanat.
He has been held in Bangkok Remand Prison since he surrendered himself to authorities on Nov 23.
The plan to charge Mr Chaiyanat with money laundering followed the arrest on Saturday of his wife, Pol Col Wanthanaree Kornchayanant, who was also charged with money laundering.
Nine other people were also arrested on Saturday over their alleged involvement in "grey businesses" linked to Mr Chaiyanat, according to OAG deputy spokesman Kosonlawat Inthuchanyong.
They were identified as Sitthipaibul Khamnil, Patcharin Itthiwatana, Sitthipong Thuesatthiang, Chutiphon Janchaithanatip, Surasawadee Thongpermploy, Peerapat Thongpermploy, Sitthikorn Prapacharaswong, Chatchai Lap-amnuaycharoen and Nathawut Sri-on.
They were taken to Bangkok South Criminal Court on Monday after investigators asked the court to extend their detention for further questioning.
Mr Kulthanit said those arrested on Saturday were among the 15 suspects sought by the OAG over their alleged connection with drug trafficking, money laundering and other transnational criminal activities as the probe into the gang's activities expands.