Public prosecutors say they dropped murder and other serious charges against former Kaeng Krachan National Park chief Chaiwat Limlikit-aksorn and three others in connection with the killing of Karen activist Porlajee "Billy" Rakchongcharoen due to lack of evidence.
An Office of the Attorney-General (OAG) panel said last week it had dropped seven serious charges against the four, including premeditated murder and concealing the body of the activist, who disappeared in 2014.
The announcement prompted several people to question the decision, resulting in the OAG panel providing an explanation on Monday.
The panel indicted the four only for negligence for failing to hand Porlajee over to police after they detained him in April 2014 for collecting wild honey in the park, in Phetchaburi's Kaeng Krachan district .
OAG deputy spokesman Prayuth Phetchakhun said the panel considered forensic evidence from the Department of Special Investigation (DSI), particularly a DNA test on skull fragments believed to be Porlajee's which matched his mother's DNA.
However, the panel felt the evidence was not enough to verify Porlajee's identity, so there wasn't sufficient evidence linking his alleged murder to the four suspects, Mr Prayuth said.
On Sept 2, 2015, the Supreme Court upheld two lower court rulings dismissing a case against the four suspects over Porlajee's disappearance, Mr Prayuth added. The suit was filed by Porlajee's wife, Pinnapa Prueksapan, who alleged the four were not only involved in her husband's disappearance, but were still holding him.
The court was convinced by testimony from Mr Chaiwat, park officials and two student trainees that Porlajee had been released contrary to what Ms Pinnapa was claiming.
However, the DSI last year found the skull fragments in Kaeng Krachan reservoir in Phetchaburi and later launched a murder probe with the four as prime suspects. Mr Prayuth said Ms Pinnapa can still press murder charges against the four suspects herself and prosecutors stand ready to help her.
The DSI and forensic experts defended their investigation, saying the DNA tests and lines of inquiry that resulted from them were sound.
Pol Lt Col Sethsathit Suwanagoot, deputy chief of the DSI's regional operation bureau, said witnesses questioned have confirmed that all Porlajee's matrilineal relatives are still alive, with only Porlajee missing.
