Bangkok, Thailand (CNN) — Six people, including two US citizens, who were found dead inside a luxury hotel room in central Bangkok likely drank from tea and coffee cups laced with cyanide following a dispute linked to bad investments, Thai police said Wednesday.
The grisly discovery was made on Tuesday when staff at the five-star Grand Hyatt Erawan in the Thai capital entered the fifth-floor suite after the guests missed check out by more than 24 hours.
When police arrived at the scene, they found the bodies of three men and three women, a table full of untouched food wrapped in plastic and used cups with traces of a white powder. The door was locked from the inside, police said, though a backdoor was left unlocked.
Authorities initially said they were searching for a seventh person who was part of the hotel booking. But on Wednesday they dismissed this line of inquiry, saying they believe one of the deceased poisoned the others with the deadly fast-acting chemical cyanide.
Among the dead are two Vietnamese Americans and four Vietnamese nationals including a married couple aged between 37 and 56, Thai police said.
Chief of the Police Forensic Office Trairong Phiewphan said in a press conference that cyanide was found in mugs and cups in the hotel room and at least one of the blood samples collected from a deceased man had traces of the chemical.
“Cyanide was found in the liquid inside the teapot, in all six coffee cups,” Trairong said.
Images issued by the Royal Thai Police showed cups on a coffee table next to two metal thermos flasks and a dining table laden with plates of food, prepared as if people were about to sit down to eat.
The question police are now trying to answer is whether the victims were murdered or chose to take their lives. Wednesday’s press conference suggested police were leaning toward the former.
Deputy Metropolitan Police Commissioner Noppasin Poonsawat told reporters they believe one of the members of the group may have poisoned the five others.
That person, police said, had ordered the food and tea to the room and “looked under stress” when staff arrived.
Noppasin said from interviews with hotel staff, one of the members of the group was alone in the room when the food arrived and was later joined by the other guests.
He added that the incident was likely linked to a “personal matter” and not related to organized crime as interviews carried out with relatives of the dead indicated a dispute over debt.
“One of the relatives said one of the deceased was an investment agent and all (the deceased) invested, but the business was not going as expected. They made an appointment to discuss the matter in Thailand,” Noppasin said.
Two of the deceased were found in the bedroom, another at the dining table, and police believe one member of the party tried to reach the door but fell before they were able to do so.
Police said the group had arrived in Thailand on various dates and had booked separate rooms at the hotel. On July 15, the party all moved into the same room and had room service delivered at about 2 p.m. local time. No one left or entered the suite after 2:17 p.m., according to police.
The Grand Hyatt hotel, where the deaths occurred, is located in a bustling tourist area in the heart of Bangkok that’s home to luxury shopping malls and restaurants.
Next to the hotel is the Erawan shrine, a famous landmark popular with Buddhist, Hindu and Sikh communities and tourists. The shrine, a preferred spot for those seeking good luck, was also the target of a bombing in 2015 that killed at least 20 people.
The US State Department said it was “aware of reports of the deaths of two US citizens in Bangkok” and Reuters reported that Vietnam’s government said its embassy in the Thai capital was closely coordinating with Thai authorities.
“We offer our sincere condolences to the families on their loss. We are closely monitoring the situation and stand ready to provide consular assistance to those families,” US State Department spokesperson Matthew Miller told a briefing Tuesday.
Last year Sararat Rangsiwuthaporn, a Thai woman who was arrested on suspicion of murdering her friend with cyanide, was charged with at least 13 counts of premeditated murder, in a separate poisoning case that stunned the country.
