Pol Lt Gen Surapol Tuanthong, chief of the Bureau, said on Saturday that officers searched two vehicles at a rented house in tambon Ban Du of Muang district and found half a million pills in one vehicle.
Police arrested Weerayuth Fahrungthaweesup, 25, and his brother Weerachai, 21, along with Adulwit Wongnaphapaisal, 35, and a 17-year-old teenager identified only as “A”.
Officers had received a tip about the transport of the drugs by two vehicles and followed them to the house.
The suspects confessed that they had received the drugs from Akha hilltribesmen in Mae Chan district in order to deliver to dealers in Ayutthaya province.
The police believed that the pills were part of the same lot as drugs seized in Ayutthaya last week. They suspect that the drugs are produced in Myanmar under the Yise group as the packages bear the symbol “999”.
Investigations have determined that the lot totalled 6 million pills and more than half have been seized by Thai police.
The police did not disclose the value of the latest seizure but it wais estimated that the drugs would have a street value of around 90 million baht.