Chada Thaiseth, a former Uthai Thani MP, reportedly has been on an official list of mafia-style figures.
More than 100 policemen, both in uniform and plainclothes, intercepted his convoy on a road in Uthai Thani province on Saturday afternoon.
Chada’s group was driving as many as eight vehicles and a search found several guns and illicit drugs in the cars.
“Chada was not carrying any weapon or illegal items,” his lawyer Suparerk Iamla-or on Sunday.
Suparerk said the guns were being held by members of Chada’s entourage.
He added that the man who was found in possession of illicit drugs had asked for a ride to a funeral.
“The drugs suspect remains in police custody,” Suparerk said.