By Natthawat Laping
Officers at the checkpoint on a rural road in Tambon Mae Fa Luang spotted four men on two motorcycles riding a kilometre from the Thai-Myanmar border at around 9pm.
When authorities waved for the men to stop and submit to a search, they sped up and officers gave chase, catching one man who had been riding pillion on the second motorcycle.
A subsequent search of the area discovered three backpacks containing 400,000 yaba pills in a nearby ditch.
The unnamed suspect reportedly confessed that he and the other men had picked up the drugs from the border area in Ban Lise to deliver to a person at Ban Huai Khrai in Mae Sai district.
As officers hunted for the other suspects on Monday morning, they found another sack containing 100,000 yaba pills at the Suan Rukkhachat Intersection.