Pholachi “Billy” Rakchongcharoen was last seen at Kaeng Krachan National Park in Phetchaburi province on April 17, 2014.

Pholachi is known to have had a dispute with Chaiwat Limlikitaksorn, the park’s chief, as he encouraged Karen-ethnic people living around the park to file a complaint against the official over alleged abuses.

Park officials have consistently insisted that they detained Pholachi only briefly and released him.

His wife, Pinnapa Prueksaphan, has lodged complaints with several agencies in the belief that park officials are responsible for her husband’s disappearance. Investigations have been launched but there has been no significant progress in the case.

Earlier this year, Pinnapa received an official letter from the DSI informing her that it has resolved not to accept the disappearance of Pholachi as a special case.

Pol Lt Col Korrawat Panprapakorn, who heads the DSI Bureau of Regional Operation Centre, confirmed yesterday that the letter had been sent to Pinnapa. “A fresh investigation will be launched again only if new evidence is found,” he said.

Korrawat explained that although traces of human blood were found on a vehicle belonging to the Kaeng Krachan National Park, it was not possible to verify if the blood belonged to Pholachi “because the vehicle had been cleaned before it reached the hands of forensic experts”.

Korrawat said the DSI had also checked recordings from security cameras around the park but these were not clear enough to identify the faces of persons inside the vehicle.

“DSI officials have also questioned 200 villagers and potential witnesses. But none of them has provided useful information,” he said.