Anti-narcotics officials have arrested four people, confiscated 1.7 million methamphetamine pills and 300kg of crystal methamphetamine, or ya ice, during an extensive investigation into a drug network in the North.
The arrests were made at a house in Bangkok's Klong San district on Monday during a Narcotics Control Board (ONCB) raid which also uncovered large amounts of illicit drugs.
The suspects were identified as Sarayut Ekmongkolsuk, 28, Adisak Kaenthongdaeng, 24, Thiwat Klin-obchoey, 23, and Pruettichai Chaiyong, 22.
According to the ONCB, the suspects were followed from a shopping mall in Nonthaburi's Bang Yai district to the house following a tip-off that Mr Thiwat would collect drugs from there.
Mr Thiwat was suspected of moving drugs from the north to Bangkok's Thon Buri district before distributing them to customers in Bangkok, nearby provinces and the South.
The arrests were linked to a drug seizure in Chiang Rai's Chiang Saen district on April 27 when narcotics suppression officials grabbed more than 4 million speed pills, 100kg of crystal meth and 49kg of ketamine.
On May 18, police arrested three people and seized 4 million speed pills in Trang in connection with the Chiang Rai case.
According to a police source, the drug cell arrested on Monday was run by Mr Sarayut and the confiscated speed pills were destined for distribution in Bangkok and some southern provinces, while the "ice" was believed to be destined to be smuggled abroad. The source said the investigation would be expanded as authorities believe the gang must have financial backers.
ONCB Secretary-General Sirinya Sitdhichai said this year has seen a number of drug raids on major networks and the freezing of drug-related assets as part of stepped-up efforts in combating drug trafficking. The ONCB held an auction earlier this month to sell of assets suspected of being associated with the drug trade.
The Narcotics Suppression Bureau, meanwhile, is seeking co-operation from Malaysian authorities about freezing the assets of a Malaysian executive of the MBI Group who was detained by Malaysian authorities for alleged money laundering.
Pol Lt Gen Sommai Kongwisaisuk, the bureau chief, said the southern region-based firm is suspected of laundering money for several drug networks including that of arrested Laos drug lord Xaysana Keopimpha.
Video by Somchai Poomlard