Ratthaphum Pimjaisai, 34, was found in a delirious state on December 20, then had a seizure and passed out on a traffic island on Borommaratchachonnani Road. He was later taken to a hospital. Earlier on the same day, he called his manager for help, saying he was in a soi in Bangkok’s Thawee Wattana district before he went missing.

He then went into a coma and died in the hospital 10 days later. But the man had no identification papers on him, so his body was kept at the morgue – until his identity was confirmed yesterday.

Forensic expert Dr Papanu Sitthiprasit said an autospy on the man’s body revealed no signs of assault and Rattaphum had died from liver and kidney failure, possibly from methamphetamine found in his blood.

Strands of the man’s hair have been collected to determine the amount of narcotics he consumed and how long he had been taking it. Papanu said the man’s state of deliriousness may have been caused by the drug.

Rattaphum’s father La-eard Pimjaisai, 65, has said he has no doubt about his son’s death and does not want another autopsy to be conducted on the body.

After a meeting with fellow officers yesterday, Taling Chan superintendent Pol Colonel Thanawan Taraka quoted witnesses as saying that Ratthaphum was found on the traffic island with drug overdose symptoms. Police later retrieved the man’s cellphone, Bt20,000 in cash, three gold amulets and two grams of crystal meth in the area.

Thanawan said police would continue investigating the case and see if anybody could provide clarity for the circumstances of his death for the family.