The parents of a student at the Armed Forces Academies Preparatory School have demanded an explanation for the death of their son and the disappearance of his brain and internal organs from his body.
Pichet and Sukanya Tanyakan, both well-known racing drivers, revealed the circumstances of the death of their son to the media on Monday.
Mr Pichet said he was informed by the military that his son, Pakapong Tanyakan, 18, a first-year student at the academy, had died on Oct 17.
The academy gave no other details, only a death certificate giving sudden cardiac arrest as the cause of death. This raised his suspicions.
He said his son had previously told him he was often disciplined by a senior student at the military academy. In one instance, the severity of the punishment caused his heart to stop beating briefly.
However, Mr Pichet said he did not think this had anything to do with his son's death.
Ms Sukanya said her son was once ordered to stand on his head on the floor of a toilet, with his feet up in the air, as a punishment. He had gone into shock and had needed cardiopulmonary resuscitation (CPR) to revive him.
She did not know why her son was disciplined, or how long he had been made to remain in that position.
The body of their son was brought home for funeral rites at Wat Wiwekaram in Chon Buri's Sri Racha district and the cremation was scheduled for Oct 24.
Mr Pichet said he secretly took his son's body out of the temple and to a hospital for an autopsy before the cremation, which proceeded without anyone knowing the coffin was empty.
Suphitcha Tanyakan, the elder sister of Pakapong, said the autopsy found that some internal organs were missing - including his heart, stomach and bladder - and the brainpan in the skull was empty, filled only with tissue paper.
The autopsy also found his fourth rib was broken and major internal bruising to the right side of the abdomen, and left side of his back. Both collarbones were broken, Ms Suphitcha said.
All of which fuelled further suspicion about the circumstances surrounding Pakapong's death.
Doctors who performed the autopsy said the broken rib could not have been caused by CPR and the bruising was likely caused by severe blows, Ms Suphitcha said.
The family also played to the media a sound recording which they said was a conversation between them and the superintendent of the Armed Forces Academies Preparatory School after they learned about the disappearance of Pakapong's internal organs.
They want the missing organs returned and an inquiry into the actual cause of death and subsequent events.
On Tuesday Deputy Prime Minister and Defence Minister Prawit Wongsuwon was reportedly visibly shocked when reporters asked him about this case.
Gen Prawit said the Supreme Commander had not yet reported the matter to him.