Initial autopsy results revealed traces of cyanide in the blood of six Vietnamese and American guests found dead in a luxury hotel in central Bangkok, with Thai authorities now suspecting that one of the victims poisoned the others over a bad investment.

The bodies were discovered on Tuesday at the Grand Hyatt Erawan Bangkok, and the six victims were last seen alive when food was delivered to their room on Monday afternoon, according to ABC News.

Hotel staff reported seeing a woman receive a delivery of food, with security footage showing the rest of the group arriving shortly after. The door to the room was locked from the inside, and no visitors were observed leaving the premises.

Traces of Cyanide Found in Blood and Cups

A maid found the bodies on Tuesday afternoon after the guests failed to check out. The food from the previous day was untouched, while several used teacups and two thermos bottles were found on a nearby table. Authorities found evidence of cyanide in the drink containers. Initial autopsy results confirmed the presence of cyanide in the blood of all six victims, with no signs of blunt force trauma.

"There were traces of cyanide in the cups and bottles," said Lt. Gen. Trairong Piwpan. The cyanide was likely the cause of death, according to the medical team.

Victims Identified, Possible Motive Suggested

The victims were identified as three men and three women, aged between 37 and 56. They included two Vietnamese Americans and four Vietnamese nationals.

A husband and wife among the deceased had invested about 10 million baht with two of the others, which could provide a motive for the poisoning. Bangkok police suggested one of the six might have poisoned the others, but they did not identify the suspect.

Four bodies were found in the living room and two in the bedroom. Two of the victims appeared to have tried to reach the door before collapsing.

Seventh Person Believed to Be Uninvolved

A seventh person, whose name was part of the hotel booking, left Thailand on July 10 and is believed to have no involvement in the incident. Both the Vietnamese and United States embassies have been contacted.

The American FBI is en route to assist with the investigation. Prime Minister Srettha Thavisin emphasized that the incident was not an act of terrorism or a breach in security.

"This wasn’t an act of terrorism or a breach in security. Everything is fine," said Prime Minister Srettha Thavisin.

Investigation Continues as Authorities Seek Answers

The possibility of a mass suicide has been ruled out, as some victims had arranged future parts of their trip. Lt. Gen. Trairong Piwpan noted, "A mass suicide was unlikely because some of them had arranged future parts of their trip."

The U.S. State Department offered condolences and is closely monitoring the situation. "The U.S. is closely monitoring the situation and would communicate with local authorities," stated U.S. State Department spokesperson Matthew Miller.

Bangkok police chief Lt. Gen. Thiti Sangsawang described the scene, saying, "Four bodies were in the living room and two in the bedroom. Two of the people appeared to have tried to reach the door but collapsed before they could."

Ongoing Investigation by International Authorities

The case appears to be personal and would not impact the safety of tourists, according to Bangkok authorities. "The case appeared to be personal and would not impact the safety of tourists," said Noppasin Punsawat.

Forensic teams continue to analyze evidence, and investigators are working to piece together the timeline of events leading to the tragic deaths. The luxury hotel remains under heightened scrutiny as the investigation progresses.

Authorities are urging anyone with information to come forward as they work to solve this complex case. The collaboration between Thai authorities and international agencies underscores the seriousness of the investigation.

Conclusion: Comprehensive Summary of Events

Six Vietnamese and American guests were found dead at the Grand Hyatt Erawan Bangkok, with initial autopsy results revealing cyanide poisoning.

Thai authorities suspect one victim poisoned the others due to a bad investment. The U.S. FBI and Thai police are collaborating on the ongoing investigation, which has ruled out terrorism and mass suicide.

International authorities remain involved, emphasizing that the incident will not impact tourist safety.