The multiple murder is thought to be connected to a joint investment in a Japanese hospital construction project.
Initial autopsy results have identified traces of cyanide in the blood of six Vietnamese and American guests found dead at a central Bangkok luxury hotel, with Thai authorities saying one is believed to have poisoned the others over a bad investment.
The bodies were found on Tuesday in the Grand Hyatt Erawan Bangkok, a landmark at a central intersection in the capital busy with malls, government buildings and public transit.
Bangkok police identified the dead as two Vietnamese Americans and four Vietnamese nationals, all between 37 to 56 years old.
Among the dead were a husband and wife who had invested about 10 million baht (€254,816) along with two of the others in a hospital to be built in Japan, and authorities believe the group might have been meeting to settle the matter.
The six were seen alive when food was delivered to the room on Monday afternoon. The staff saw one woman receive the food, and security footage showed the rest arriving one by one shortly after.
There were no other visitors, no one was seen leaving, and the door was locked. A maid found them on Tuesday afternoon when they failed to check out of the hotel.
Trairong Piwpan, chief of the Thai police force’s forensic division, said there were traces of cyanide in the cups and thermos flasks that police found in the room. This was later confirmed by the initial autopsy results.
The police say one of the group killed the others but did not say which is the suspect.
Trairong said a mass suicide was unlikely because some of the dead had arranged future parts of their trip, such as guides and drivers. He added that the bodies being in different parts of the hotel room suggested they did not knowingly consume poison and wait for their deaths together.
Kornkiat Vongpaisarnsin, head of the forensic medicine department at Chulalongkorn University’s medical school, said at a news conference that there was cyanide found in the blood of all six bodies and that CAT scans had revealed no signs of blunt force trauma.
Thai Prime Minister Srettha Thavisin said the Vietnamese and US embassies have been contacted regarding the deaths, and that investigators from the American FBI were en route to Thailand.
He said the case would likely not affect a conference with Russian Energy Minister Sergei Tsivilev at the hotel later Wednesday.
“This wasn’t an act of terrorism or a breach in security,” he said. “Everything is fine.”
Last year, Thailand was rocked by reports of a serial killer who poisoned 15 people with cyanide over a span of several years.
Sararat Rangsiwuthaporn, or “Am Cyanide” as she would later be called, killed at least 14 people to whom she owed money and became the country’s first known female serial killer. One person she targeted survived.
