On Tuesday, police in the Northeast border province of Mukdahan announced they had seized 384 kilogrammes of crystal meth worth Bt150 million after being tipped off.
Responding to a report that a smuggling operation was underway, officers began searching a secluded spot by the river on Sunday.
They then received another report that a 10-wheeler truck had been spotted by the riverside. Officers raced to the spot and opened the truck to discover the huge haul of drugs piled inside.
Police arrested the driver and are now hunting for two more suspects.