King Ananda, also known as Rama VIII, reigned from 1935 to 1946, and was the uncle of the present Thai monarch Maha Vajiralongkorn and the elder brother of the last King Bhumibol Adulyadej.
Ananda, who was found lying face up in bed with a gunshot wound on his head on June 9, 1946, was murdered, according to official investigations and three court verdicts that concluded in 1954.
Three palace officials were found guilty of being accessories to the king's murder and were executed in 1955. The three men pleaded not guilty and no one else stood trial.
Initial investigations by police blamed a conspiracy plot led by Pridi Banomyong, who was the prime minister when the king died. Pridi went into exile and died in France in 1983, but he was later essentially exonerated by the government, which nominated him in 1997 to the UNESCO millennium list of great personalities of the 20th century.
Hearings on the petition to reopen the case were held at the Bangkok criminal court on Thursday and were due to continue on Friday. It is the first time an attempt is being made to revive the investigation directly through a court order.
The petition was filed by Kungwal Buddhivanid, 62, a trained chemist and a former business executive who in 2020 published a book challenging the official explanation that the king died from regicide. His book, which was published and distributed in Thailand, revived a previously dismissed possibility that the king shot himself.
Kungwal, who lives near Bangkok, said in court that he could prove that the king’s gun, found next to his dead body, was the weapon that killed him. The original investigators in the 1940s said the king’s gun was fired days before his death and that Ananda was killed by another gun that was never found.
"The old verdicts dismissed the idea of a suicide and ruled that it was regicide," Kungwal told the court.
"New evidence I bring will show differently," he said, referring to ballistic tests he conducted last year with a retired police forensic expert that he says prove that the king shot himself with his own gun found next to his body.
Reuters did not view the test results and could not independently verify Kungawal's claims. Wasukit Thanurat, the forensic expert, was not immediately available for comment but was due to testify in court later on Friday.
More than two dozen books have been written over the decades about the death of King Ananda, with several scholars challenging the official narrative on the grounds that the investigation was not transparent and was mired by the politics of the day.
Some of the books were published and distributed in Thailand, mostly in the 1970s, others were banned by the authorities. Thailand has a strict lese majeste law that prescribes up to 15 years jail for defaming or insulting the monarchy.
Kungwal petitioned the court last October to revive the case on behalf of the relatives of Chit Singhaseni, one of the palace officials executed.
After the hearings, the four judges presiding over the hearing will send the case to the court of appeal, which will decide whether to reopen the case or not.
Watsatarn Kittipinyo, Chit's granddaughter, was present in court on Thursday. She told Reuters that she has no expectations from the case other than a hope that her grandfather's name could be cleared.
