An official autopsy on environmental activist Sutthi Atchasai confirmed he committed suicide, the Central Institute of Forensic Science (CIFS) revealed yesterday.
Suwanarong Srisuwan, a CIFS forensic expert, said the bullet that killed Sutthi penetrated the right temple and lodged close to his left temple.
The autopsy also showed the bullet was fired from a gun that was pressed against Sutthi's skin which led the forensic team to believe it was suicide rather than murder as was suspected by some, Dr Suwanarong said.
No other wounds were found on the body, the doctor said.
Sutthi's body was taken from Wat Treemitpradittharam in Rayong to Bangkok on Monday for the autopsy after his family postponed the cremation because of emerging doubts over his alleged suicide.
A source close to the family said the cremation was postponed because the ballistics report threw up several questions that needed to be answered.
The activist was found with a gunshot wound to the head on July 15 in his pickup truck in the garage of his home in Rayong's Muang district. A .38 revolver was found in his right hand. He was taken to Rayong Hospital and pronounced dead the following morning.
Police said four shots were fired. One penetrated Sutthi's right temple. The other three passed through the vehicle's windscreen and through the garage roof.
At first, his mother, who talked to Sutthi shortly before his death, ruled out murder and believed her son killed himself due to stress.
However, a police ballistic report raised doubts. Some family members believed the trajectory of one of the shots that went through the roof indicated Sutthi might not have fired it from where he was found.
They questioned why he fired three shots before shooting himself.
The family want police to trace where the gun came from because they are not sure if it belonged to Sutthi, the source said.