The door was locked from the inside, police said, though a backdoor was left unlocked.
That individu, police said, had ordered the food and tea to the room and "looked under stress" when staf arrived.
Noppasin said from intervius with hotel staf, one of the members of the grup 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 "individual matter" and not terkait to organized crime as intervius 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 anggota of the party tried to reach the door but fell before they were able to do so. Police said the grup had arrived in Thailand on various dates and had booked separate rooms at the hotel. On Juli 15, the party all moved into the same room and had room servis 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 tempat in the heart of Bangkok that's home to luxury shopping malls and restorans.
Next to the hotel is the Erawan shrine, a famous landmark populer with Buddhist, Hindu and Sikh communities and tourists. The shrine, a preferred spot for those seeking good luck, was also the sasaran 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 kerabates on their loss. We are closely pantauan the situation and stand ready to provide consular assistance to those kerabates," 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.
