Six persons found dead in a central Bangkok luxury hotel had cyanide traces in their blood, according to forensic experts.
The bodies were discovered at the Grand Hyatt Erawan Bangkok.
Officers stated that after reviewing hotel records and surveillance footage, there were no additional visitors to the room than the six people who were discovered dead.
Doctors who conducted post-mortem investigations on the six visitors verified the presence of cyanide in their blood.
At a press briefing, Dr. Kornkiat Vongpaisarnsin, the chairman of the forensic medicine department at Chulalongkorn University’s medical school, stated that the theory that the deceased had been poisoned was strengthened by the fact that a CAT scan revealed no evidence of blunt force damage.
The head of the forensic branch of the Thai police force, Lt Gen Trairong Piwpan, had earlier stated that cyanide residue was discovered in cups and other containers that had been discovered in the room.
Lt Gen Thiti Sangsawang, the chief of Bangkok police, described the deceased as three males and three women, as well as two Vietnamese Americans and four Vietnamese nationals.
Their ages ranged from 37 to 56, according to Noppasin Punsawat, Bangkok deputy police chief. He said the case appeared to be personal and would not impact upon the safety of tourists.
The Vietnamese and US embassies have been contacted over the deaths, and the American FBI is enroute, said Prime Minister Srettha Thavisin.
A husband and wife among the dead had invested money with two of the other victims, suggesting that money could be a motive, said the police chief.
The investment was meant to build a hospital in Japan and the group might have been meeting to settle the matter.
The six had last been seen alive when food was delivered to the room on Monday afternoon.
The staff saw one woman who received the food, and security footage showed the rest arriving one by one to the room shortly after.
No-one was seen leaving and the door was locked from the inside. A hotel maid found the bodies on Tuesday afternoon when they failed to check out of the room.
Officers said a seventh person whose name was part of the hotel booking was identified by police as a sibling of one of the six victims, who left the country on July 10. Police believe the seventh person had no involvement in the deaths.
