Rayong police said they had arrested a factory worker who allegedly dropped anti-coup leaflets on roads and in several other places in Muang district on March 22.
The man was identified as Ponlawat Warodomputhikul, 22, who lives in tambon Thab Ma of Muang district, Pol Maj Gen Chumphon Chanthachamrassil, chief of Rayong police, said on Saturday.
He said police and military officers had carried out a week-long investigation until they were certain that Mr Ponlawat was the person who distributed the leaflets in the early-morning hours last Sunday.
Mr Ponlawat was arrested on Friday and taken to a military camp for questioning. He was being escorted to Muang Rayong police station on Saturday night to face further legal proceedings.
Pol Maj Gen Chumphon said the man admitted to distributing the leaflets.
Mr Ponlawat graduated from Rayong Technical College and currently works at a petrochemical factory in the province, the officer said, without giving other details.
The leaflets containing anti-coup messages were scattered in several places including a location near the Rayong police station and the Muang district office. Most bore the message "Down with the dictatorship. Long live democracy".