![](https://media.nbcnewyork.com/2024/07/download_c820fa.webp?crop=0px%2C25px%2C1440px%2C810px&resize=320%2C180&quality=85&strip=all)
Investigators believe six Vietnamese and American guests who died at a luxury Bangkok hotel were poisoned with cyanide, after traces of the poison showed up in an initial autopsy, Thai authorities said Wednesday.
In a press conference Wednesday, Bangkok Police Lt. Gen. Thiti Sangsawang identified two American dual nationals among the three Vietnamese men and three Vietnamese women who had died. Police said they were between 37 and 56 years old.
![](https://media-cldnry.s-nbcnews.com/image/upload/t_fit-560w,f_auto,q_auto:best/rockcms/2024-07/240717-bangkok-hotel-mb-0854-f83a44.jpg)
Thai Prime Minister Srettha Thavisin said that the United States and Vietnamese embassies had been contacted over the deaths, and that the FBI was enroute to investigate, according to The Associated Press.
The bodies were found by a maid Tuesday when the guests failed to check out. The door to the room at the Grand Hyatt Erawan, Bangkok, was locked from the inside. Police, who found traces of cyanide in the tourist’s teacups, a tea flask and the blood of one of the dead men, said there was no sign of a struggle and that a full autopsy report is expected Thursday.
![](https://media.nbcnewyork.com/2024/07/AP24198636943426_61819f.jpg?quality=85&strip=all&resize=218%2C123)
Get Tri-state area news delivered to your inbox. Sign up for NBC New York's News Headlines newsletter.
Police interviews revealed that four of the six victims had invested money together and that there may have been a dispute over debt relating to the investment. Noppasin Punsawat, Bangkok's deputy police chief, told a press conference that the investment had been intended to build a hospital in Japan.
U.S. & World
Given the personal nature of the situation, Noppasin said the case would likely not affect a conference with Russian Energy Minister Sergei Tsivilev set to take place at the hotel later Wednesday. “This wasn’t an act of terrorism or a breach in security. Everything is fine,” he said.
The men and women were last seen alive Monday afternoon when staff brought food and drinks to the room. CCTV footage then showed the six entering the room before closing the door for the last time.
![](https://media-cldnry.s-nbcnews.com/image/upload/t_fit-560w,f_auto,q_auto:best/rockcms/2024-07/240717-bangkok-hotel-mb-0852-3ca8d8.jpg)
Lt. Gen. Trairong Piwpan, chief of the Thai police force’s forensic division, said that police have ruled out a mass suicide because members of the group had arranged activities with guides and drivers. He added that the six bodies were found in different parts of the room, meaning it was unlikely that they had intentionally consumed the poison and waited to die.
In 2023 in Thailand, a serial killer named Sararat Rangsiwuthaporn, also known as “Am Cyanide,” was charged with poisoning 15 people with the deadly chemical, which interferes with the body's ability to absorb oxygen, over a number of years. She killed at least 14 people whom she owed money to with one person surviving, the Associated Press said. She was the nation’s worst serial killer and its first female one.
This article first appeared on NBCNews.com. More from NBC: