A man and a woman linked to a major drug bust in the northern province of Phayao in 2018 have been arrested, Office of the Narcotics Suppression Board (ONCB) secretary-general Niyom Termsrisuk said on Wednesday.
Mr Niyom identified the man only as Phayao and the woman as Sureerat.
He said they were arrested on Jan 15 in Nakhon Pathom province following a joint intelligence operation by the ONCB, the Narcotics Suppression Bureau (NSB) and Armed Forces Security Centre (AFSC).
In September 2018, a combined government unit intercepted two vehicles - an ambulance and a rescue-unit pickup - in Phayao and seized 398 kilogrammes of crystal methamphetamine, or ice, and 81kg of ketamine.
Seven suspects were arrested, but they were found to be only hired couriers. Following an expanded investigation, court arrest warrants were obtained for Mr Phayao and Ms Sureerat.
During the investigation, it was learned that Mr Phayao was about to smuggle a large quantity of crystal meth into the country over the western border. This led to the seizure of about 1,500kg of ice and the arrest of one suspect at a warehouse in Pathum Thani province in June last year.
The on-going investigation then led to the arrest of Mr Phayao and Ms Sureerat on Jan 15, said Mr Niyom.
Their assets would be seized for investigation and the search would continue for the network's masterminds, he added.