Pol Lt-Colonel Thitiwat Ruechanukul, deputy Chiang Mai immigration police chief, said Nan Nyo, 34, was arrested at the Chiang Mai bus terminal in Muang district on Tuesday.
Thitiwat said Nan was arrested while picking up three Myanmar people at the bus terminal. The three were identified as Pan, 30, Kham, 50 and Aung Lu, 27.
The three told police that they promised to pay Nan Bt3,400 each to drive them back to Myanmar in her pick-up truck.
Thitiwat said the four had sneaked across the border into Chiang Rai’s Mae Sai district.
Nan had allegedly sneaked into Thailand on her own and had been helping undocumented Myanmar migrants return to Myanmar, while the other three had allegedly sneaked in three months ago and wanted to return to Myanmar after working for three months, Thitiwat said.