The military junta and the Public Relations Department on Thursday inspected the Confidante community radio station hours after ousted premier Thaksin Shinawatra called to talk to listeners on-air. The station then went silent.
Council for National Security chairman Sonthi Boonyaratkalin said that he assigned the Internal Security Operations Command (Isoc) to find more information on the radio station and report to the CNS.
In the broadcast, which was repeated by the Confidante station just before it went off the air, Mr Thaksin called for an early election, and said people would not tolerate any delays in the election, points he has made in previous interviews overseas.
Bavorn Techa-in, chief of the National Broadcasting Commission which is under the government's PRD, said he was assigned to inspect the station, which is in the northern Bangkok suburbs in Nonthaburi province.
Mr Bavorn said the station had been set up unlawfully. He denied, however, that there was any order to shut down the station.
Mr Bavorn may have been economical with the truth. Other media reports quoted the chief of the PRD as saying he had issued an order to close down the radio station.
Either way, Confidante radio stops airing its program on Thursday afternoon. One report quoted staff as telling the PRD inspectors that broadcasting equipment was broken, and they had to send it out for repairs on Thursday morning.
The inspectors seized a tape recording of the 15-minute call and talk by Mr Thaksin, who phoned the station from London late on Wednesday.
Mr Thaksin called the low-powered community radio station, which can be heard in many parts of Bangkok.
Announcer Chupong Theethuan told the AFP news agency he was "shocked and speechless" when he realised the person on the other line was the ex-premier.
It was the first time Mr Thaksin had spoken to any Thai media since the Sept 19 coup. Mr Thaksin said he believed people would not tolerate any delays in the election.
He told the Council for National Security and the government that they need not worry about him, but instead should use their time to solve problems of the country.
He thanked his supporters and gave them encouragement to go through the problems they faced.
The content of the broadcast was not especially newsworthy. Mr Thaksin said much the same thing in interviews with the foreign media earlier this year.
The ousted premier mentioned buying Manchester City league but refused to give details. He only said it will benefit Thailand if he purchased the Premier League team, without clarifying how.