Sulak Sivaraksa, one of Thailand's most prominent writers and social critics, has been arrested for lese majesty (defaming the much-revered monarchy). The offense that carries a maximum sentence of seven years.
Mr. Sulak's arrest comes at a time of political uncertainty in Bangkok. There are rumors of coups and of conflict between prominent politicians.
After eluding the police for several days, Sulak was taken into custody Sunday. The charge stems from an interview with Sulak published in a collection of the writer's works which appeared earlier this year. The book was freely distributed until early July, when the police confiscated stocks.
Two others connected with the book were arrested last week and later released on bail.
The arrests follow the roundup in early July of 16 suspected members of the Communist Party of Thailand, several of them Central Committee members.
Shortly afterward a university lecturer, Pricha Piempongsan, was arrested. Dr. Pricha, the son of a former deputy premier, was accused of helping Communist leaders make contact with the Vietnamese Embassy in Bangkok.
Commenting on these events, one of the country's most influential newspapers, Siam Rath (State of Siam), theorized, ''There might be some influential people trying to create confusion in order to use to it to stage a coup d'etat to overthrow the democratic system.'' If this is true, the paper continued, ''These people would be no better than communists.''
''Dictatorship by a group of people,'' Siam Rath commented, ''always leads to corrup-tion.''
The Communist Party, basically pro-Chinese in its orientation, was a major threat in the 1970s but has experienced a rapid decline due to internal divisions and a successful government amnesty program.
The director general of the Thai police, Gen. Narong Mahamonda, was quoted last week as saying that the move to arrest Sulak was not connected to the Communist Party roundup.
Sulak is generally considered a social gadfly rather than a pro-communist, commenting on - and irritating - both left and right.
After the right-wing coup of October 1976, the contents of his bookstore were burned. Sulak, who had been out of the country at the time of the coup, spent most of the following year in the United States.
Like many Thai public figures, he has visited China several times in recent years. His visits to the Indochinese states, less common at a time of poor relations with these countries, have given rise to criticism from some official quarters.
Much of Sulak's writing deals with the role of Buddhism in contemporary society. He has also written on nonviolence and is well-known as a historian. As a young man he was trained in law in Britain, where he worked for a time for the BBC.