Cyanide found in teacups shared by six found dead in Bangkok hotel

Police investigating the deaths of six people found in the room of a luxury hotel in central Bangkok say they believe a member of the group poisoned themselves and others using cyanide.

Initial tests had detected cyanide, a deadly chemical that interferes with the body’s ability to use oxygen, in a tea flask, six cups and in the blood of one of the dead men, police said. Based on interviews with a relative, they believe the deaths could be related to a business dispute.

The deceased were Vietnamese, and two had American citizenship, according to the Thai authorities, who said the FBI was assisting with the investigation.

Thai police said they believed the poisonings occurred on Monday afternoon, after the group ordered food and English tea to their room on the fifth floor of the Grand Hyatt Erawan hotel in Bangkok’s commercial district.

When room service staff arrived, they saw only one of the six, a 56-year-old woman, police said. She received the food and drinks and told hotel staff there was no need to serve the tea, according to Noppasin Poonsawat, the deputy commander of the Metropolitan Police Bureau.

Shortly afterwards, CCTV showed all six members of the group gathering outside the room and then entering, the last time they were seen alive.

“It all started after 13:57 [on Monday], after the hotel staff brought six teacups, a milk pot and two flasks into the room. We found cyanide on the six cups. According to CCTV, there was no one else – apart from the six members of the group – going inside the room, and none of them were seen coming out, after 14:17,” Noppasin said.

Tests detected traces of cyanide in a tea flask, six cups and in the blood of one of the dead men. Photograph: Royal Thai police/EPA
The group of three women and three men were found dead the following day, late on Tuesday afternoon. They were discovered by a member of housekeeping staff, after they were late to check out.

The plates of food they had ordered appeared to have gone untouched, and were still sealed in clingfilm. Their luggage was packed. Police said no illegal materials had been found inside their luggage, which was searched overnight.

The group were named by media as Vietnamese nationals Thi Nguyen Phuong, 46, her husband, Hong Pham Thanh, 49, Thi Nguyen Phuong Lan, 47, and Dinh Tran Phu, 37, and the US citizens Sherine Chong, 56, and Dang Hung Van.

Police are studying wider CCTV footage to piece together a timeline of their stay in Bangkok. The FBI was supporting the investigation as two of the individuals held American citizenship, the Thai prime minister, Srettha Thavisin, said.