(BBC News) Cyanide has been found in the blood of all six people who died in a luxury hotel suite in Bangkok, say doctors after examining their bodies.
Based on the initial post-mortem examination, they say there is “no other cause” that would explain their deaths “except for cyanide”.
But further tests are being carried out to determine the “intensity” of the deadly chemical and to rule out any other toxins.
Forensic investigators had earlier found traces of cyanide on the teacups used by the victims, all of whom are of Vietnamese origin including two with dual US citizenship. Police suspect that one of the dead was behind the poisoning and was driven by crushing debt – but have not said who.
The victims’ lips and nails had turned dark purple, indicating a lack of oxygen, while their internal organs turned “blood red”, which is another sign of cyanide poisoning, said Professor Kornkiat Vongpaisarnsin of the Department of Forensic Medicine at Chulalongkorn University.
The deceased were found by housekeepers at the Grand Hyatt Erawan hotel in the Thai capital late on Tuesday. Investigators believe they had been dead for between 12 and 24 hours.
The mystery around the discovery made international headlines.
Thailand’s Prime Minister Srettha Thavisin ordered an urgent investigation into the case, stressing that the deaths were the result of a “private matter”, and there was no suggestion of public danger.
Police have since begun to piece together what might have happened.
Two of the six victims had loaned “tens of millions of Thai baht” to another of the deceased for investment purposes, authorities said. Ten million baht is worth nearly US$280,000.