On Monday, Thai police found six people dead in a luxury Bangkok hotel with no immediately apparent cause of death.
Now, local police are saying they believe they have discovered the cause of death for all six victims and have made additional breakthroughs in piecing together the details of this captivating mystery.
American Citizens Among The Deceased
The FBI, who have been assisting with the Thai investigation, confirmed that all six deceased victims were Vietnamese, but added that two of them had American citizenship.
The group of six consisted of three men and three women, whose bodies were discovered late on Tuesday after dying on Monday.
Final Moments Alive
On Monday, room service arrived and was met by a 56-year-old woman who received food and drinks and said there was no need to serve tea.
Shortly after, CCTV showed the group of six gathering outside their hotel room. The footage then showed them entering their hotel room – the last time they were seen alive.
Victims’ Names Released
The six deceased have been named 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 continuing to piece together a timeline of the deceased’s final days, while the FBI is assisting investigations because two of the victims were American citizens.
Cause of Death Revealed
Thai police have said they identified the cause of death for all six as cyanide poisoning, and believe that one member used the chemical to poison themselves and kill the other five members.
Cyanide, which disrupts the body’s ability to use oxygen, was detected in a tea flask, all six cups of the deceased, and in the blood of one of the dead men.
Investigators Speak Out
Noppasin Poonsawat, the deputy commander of the Metropolitan Police Bureau, gave details of the timeline of the case. He said, “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.”
He added, “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.”
One Theory Ruled Out
Police are continuing to study CCTV to piece together a timeline of the six members’ stay in Bangkok. However, investigators have already been able to rule out one theory.
“The incident is not related to terrorism or lack of security measurement, so I think everything will go as schedule,” said Thai Prime Minister Srettha Thavisin.
A Seventh Person Gains Attention
Police had previously been searching for a seventh person who was supposed to check in with the group of six, but never showed.
However, she is no longer suspected of being involved in the deaths in any way – having been identified as a younger sister of one of the victims, who returned home to Vietnam before the killing.
Police Reveal Motive For Killing
Police believe a business dispute likely explains the motive for the killings. Police said a married couple in the group had loaned 10m baht ($278,025/£233,186) to another member of the group to help build a hospital in Japan.
The couple in question ran a construction company in Vietnam. The US State Department added that it was “closely monitoring the situation and stand ready to provide consular assistance.”
Another Case Provides Precedent
While the Bangkok killings have shocked Thailand, and the wider world, this is not the first notable mass killing using cyanide in Thailand in recent years.
Last year, Sararat Rangsiwuthaporn was charged with 14 counts of murder via cyanide poisoning. It marked one of the country’s worst suspected serial-killing cases.
