Six American and Vietnamese guests found dead in Bangkok hotel were poisoned with cyanide after business feud: cops

The six American and Vietnamese guests found dead at an upscale Bangkok hotel were killed with cyanide — with one of them believed to have poisoned the others over a bad investment, Thai police revealed Wednesday.

Traces of the rapid-acting chemical were uncovered during the autopsies and on drinking glasses and a teapot found inside a room at the five-star Grand Hyatt Erawan hotel where the bodies were discovered late Tuesday, cops said.

Relatives of the three women and three men told investigators there had been a dispute among the group about debt tied to an investment, Bangkok deputy police chief Noppasin Punsawat said.

A husband and wife who were among the dead had invested about 10 million baht ($278,000) with two of the others to build a hospital in Japan — and they may have been meeting at the hotel to settle the matter, he added.

Police said one person poisoned the rest, but have not yet revealed which of the six is the suspect.

Two of the guests — Chong Sherine, 56, and Dang Hung Van, 55 — both had US passports. The four Vietnamese nationals were identified as Nguyen Thi Phuong Lan, 47, Pham Hong Thanh, 49, Tran Dinh Phu, 37, and Nguyen Thi Phuong, 46.

The group, who had checked into the posh hotel at various points over the weekend, were last seen alive heading into the room on Monday afternoon, police said.

Security footage showed one of the women receiving a room service delivery shortly before the five others arrived, cops added. No one was spotted leaving the room in the aftermath and the door was locked from the inside.

Four of the bodies were located in the living room and two in the bedroom, Bangkok police chief Lt. Gen. Thiti Sangsawang said.

He said two of them appeared to have tried to reach for the door but collapsed before they could.

A mass suicide was unlikely because some of the group had arranged future parts of their trip — including guides and drivers, investigators said. 

One of the hotel maids made the grim discovery after the guests failed to check out on time.

Cops immediately started testing the drinks found inside the room after traces of “suspicious substances” were spotted floating in the cups and glasses.

Photos from the crime scene showed the cups and teapots strewn out across a table inside the room, while the room service food remained untouched.

The traces of cyanide were uncovered during the initial autopsies performed at Bangkok’s Chulalongkorn Hospital, officials said.

“We can assume that the six died from cyanide,” Chulalongkorn Hospital’s Kornkiat Vongpaisarnsin told reporters, adding that results of further tests would be available on Friday.

Cops are still probing how the cyanide was obtained.

Meanwhile, police had earlier said they were searching for a seventh person — also a Vietnamese national — whose name was part of the hotel booking.

They have since determined that the person, who was a sibling of one of the six killed, had left Thailand on July 10 and is believed to have no involvement in the deaths.

The Vietnamese and US Embassies have both been contacted over the deaths, Prime Minister Srettha Thavisin said, adding that the FBI was en route to help with the investigation.

US State Department spokesperson Matthew Miller offered condolences to the families of the dead.

He said the US was closely monitoring the situation and would communicate with local authorities.

With Post wires