Withayut, a radio journalist and commentator, was gunned down on April 10 in the southern city of Surat Thani.
According to police, Withayut was approached by several gunmen and shot five times as he was about to enter his radio studio to begin his popular morning program, "Catch Up With the World." Withayut's program was carried on Fourth Army Radio, the regional affiliate of the Royal Thai Army Radio and Television network.
Surat Thani police believe Withayut, 56, was killed as a result of his reporting on irregularities involving a 50 million baht (US$1.1 million) real estate deal for a municipal garbage dump. The reports began in 1999 and eventually led the Interior Ministry to investigate and to order a portion of the money returned to the government.
Police arrested two men in connection with the shooting, one of them a municipal official implicated in the garbage dump scandal.
A well-known radio commentator in southern Thailand, Withayut was for many years a correspondent for the Bangkok-based, Thai-language Daily News before starting his radio program. Police said the journalist had received numerous death threats and was under police protection prior to the murder. However, Withayut's protection was lifted shortly before the killing, according to several Thai newspapers.