The case began when police in Samut Prakan province arrested a Thai drug dealer, said Surapol Thuanthong, deputy commissioner of the Narcotics Suppression Bureau.
Sarawut Mankong, 28, was caught with five kilogrammes of ya ice and confessed that he distributed the drugs in the Ram Intra and Lat Plakao areas, according to Pol Maj Gen Surapol.
After questioning Sarawut, police were able to arrest five more suspected dealers in Samut Prakan. They are all from Shan state in Myanmar. Officers also confiscated 11 kilogrammes of crystal meth and 790,000 speed pills.
Later, police in Nonthaburi arrested Duanghatai Kaewpet, a Thai woman who was part of the gang and seized 10,000 ya ba pills.
Police said the suspects admitted the drugs had been smuggled from the northern border of Thailand. They were then stored in Phra Pradaeng district of Samut Prakan before being distributed to different areas in Bangkok and nearby provinces.
They said they were hired by the drug gang in the North to deliver the drugs for 300,000 baht.