Cyanide poisoning caused the deaths of six people who died in a luxury hotel suite in Thailand, local police have said.
The bodies of two American and four Vietnamese nationals were discovered by housekeepers at the Grand Hyatt Erawan in central Bangkok on Tuesday.
The deadly chemical was found on drinking glasses and a teapot in the hotel room, police said. Authorities suspect money and debt were the driving motive behind the poisoning after a husband and wife had invested money with two of the other victims.
“We found cyanide in the teacups, all six cups we found cyanide,” Maj-Gen Trirong Phiwpan, commander of the Thai police evidence office, told a press conference.
“After staff brought teacups and two hot water bottles, milk and teapots… one of the six introduced cyanide.”
The results of a post-mortem were expected within the next day, police said.
Deputy Bangkok police chief, General Noppassin Poonsawat, said the group had checked into their accommodation separately over the weekend.
On Monday afternoon, food and tea was delivered to the room around 2pm local time (8am BST) but it appeared largely untouched and pictures emerged of it still wrapped in clingfilm. According to the deputy police chief, a waiter offered to make tea for the guests but this was refused.
Nobody was seen leaving or entering the room, before a hotel maid discovered the bodies 24 hours later.
Police say there were no signs of any forced entry or robbery.
Four of the victims are Vietnamese nationals, a married couple identified as Thi Nguyen Phuong, 46, and Hong Pham Thanh, 49, along with Thi Nguyen Phuong Lan, 47, and Dinh Tran Phu, 37.
The other two are American citizens, named by police as Sherine Chong, 56, and Dang Hung Van, 55.
Earlier reports from local media had suggested there had been a shooting, but police later dismissed these reports.
Two of the six had loaned “tens of millions Thai baht” – worth approximately £215,000 – to another of the deceased for investment purposes, authorities said.
Police, who spoke with relatives, said the married couple owned a road construction business and had given money to Mrs Chong to invest in a hospital building project in Japan.
Mr Tran, a make-up artist working for Mrs Chong, had travelled to Thailand on Friday and was due back on Sunday, before he extended his stay until Monday. Police suggested that he was also “duped” into making an investment
According to police, the younger sister of one of the victims who was part of the hotel booking had left the country on 10 July. Police are not treating her as a suspect.
The FBI is on its way to Bangkok and is assisting Thai authorities in the investigation, Thailand’s Prime Minister Srettha Thavisin has said.