Police in Thailand have found traces of cyanide on teacups in a room where six foreign nationals were found dead in a luxury hotel in central Bangkok on Tuesday.
The bodies of at least two Vietnamese-Americans and four Vietnamese nationals were found in the Grand Hyatt Erawan Bangkok, police said.
America’s FBI has joined the Thai police in investigating the deaths at the hotel, which is very popular with visiting tourists.
The victims, three men and three women, were aged between 37 and 56, according to Noppasin Punsawat, Bangkok’s deputy police chief.
Forensics officials said on Wednesday that traces of cyanide were found on cups and vacuum flasks in the suite where the bodies were discovered.
Tests are still being conducted on the victims and a formal cause of death has not been announced. But officials at the Chulalongkorn Hospital, to which the bodies were brought, said an autopsy also found traces of cyanide.
The bodies showed traces of the rapid-acting chemical and had purple lips, indicating a lack of oxygen, Chulalongkorn Hospital’s Kornkiat Vongpaisarnsin told reporters.
The Thai government said prime minister Srettha Thavisin has ordered all agencies involved to take urgent action, as the country seeks to avoid any further impact on the wider tourism industry. It said the Vietnamese and the American embassies had been contacted over the deaths.
The bodies were discovered by hotel staff after the group missed their check-out time, and police were called at around 5.30pm on Tuesday.
The six had last been seen alive when food was delivered to the room on Monday afternoon. The hotel staff said they saw one woman who received the food, and security footage showed the rest arriving one by one to the room shortly after.
Hotel staff found that food ordered from the previous day was left untouched, with some servings of fried rice still under plastic wrap. On a nearby table, several used teacups were found next to two vacuum flasks.
It has been reported that two of the victims were a husband and wife who had invested the equivalent of £213,267 with two of the other victims to build a hospital in Japan. It has been speculated that the group might have been meeting to settle the matter.
The couple reportedly suspected Vietnamese-American national Sherine Chong of cheating them due to a lack of progress in the project and decided to fix their differences in Thailand.
“The case likely stems from a debt problem. There are no other possibilities. The culprit is among the six because they were the only people who entered the room. There were no others,” police major-general Theeradej Thumsuthee told reporters.
Police said they suspect Chong may have poisoned the others with a drink brought in a flask that did not belong to the hotel.
A seventh person whose name was part of the hotel booking was identified by police as a sibling of one of the six victims, authorities said. Police say they have established that the seventh person had no involvement in the deaths.
Thai authorities have ruled out the possibility of a mass suicide as some of the victims had arranged future details of their trip, such as guides and drivers. The bodies were not grouped in the same place – some were in the bedroom, some in the living room – suggesting that they did not knowingly consume poison and wait for their death together, said Trairong Piwpan, the chief of police.
He said two of those who died appeared to have been trying to reach for the door but appear to have collapsed before they could do so.
The prime minister said the incident was not “an act of terrorism or a breach in security”, adding that “everything is fine”.
The Grand Hyatt Erawan has more 350 rooms and is located in a popular tourist district known for luxury shopping and restaurants.
More than 28 million foreign tourists visited Thailand last year, spending £25.94bn in the country, where other key sectors of the economy have slowed down since the Covid-19 pandemic.
The Thai government expects 35 million foreign arrivals this year, on the back of longer visa stay periods and visa waivers being extended to more nationalities.
The tourism sector was shaken last October by a shooting at a luxury shopping mall, close to the Hyatt, in which two foreigners were killed, prompting government measures to improve confidence.