One of the six foreigners found dead from suspected cyanide poisoning in a luxury Bangkok hotel likely also carried out the crime, Thai police said on Wednesday.
The bodies of six Vietnamese nationals -- two who also held American citizenship -- were discovered in a suite at the Grand Hyatt Erawan Hotel in the tourist centre of Bangkok on Tuesday afternoon.
"We are convinced that one of the six people found dead committed this crime," said Noppasil Poonsawas, a deputy commander of Bangkok police.
He told a news conference police believed cyanide was used as poison, and the motive for the crime was thought to be debt-related.
The mysterious circumstances surrounding the deaths of the three men and three women have fuelled wild rumours, with several local media outlets initially reporting a mass shooting incident.
But photos released by police of a bloodless crime scene showed plates of untouched Thai food, and two thermos flasks of coffee and cups.
Prime Minister Srettha Thavisin said Tuesday the crime was "a private matter", unrelated to national security, and should not affect the lucrative tourist sector.
Thai authorities are keen to improve the image of the kingdom, whose reputation as a safe tourist destination sometimes takes a hit when grisly crimes are reported.
The country has been the scene of several sordid and high-profile criminal cases, such as that of French serial killer Charles Sobhraj, nicknamed "The Serpent" and linked to at least two dozen murders -- mostly of tourists -- in the 1970s.
More recently, the son of a Spanish actor was accused of killing and dismembering the body of a renowned Colombian plastic surgeon on the tourist island of Koh Phangan.
The verdict in the trial is expected in the coming weeks.
Last October, a 14-year-old boy opened fire at the Siam Paragon mall in the same area as Tuesday's mass poisoning, killing three people.
The shooting came just days before the anniversary of a massacre at a nursery in northern Thailand that left 36 people dead and amid government efforts to bolster tourist numbers.
Some 28 million people visited Thailand in 2023, up from 11 million the year before, but still well down from the 40 million who came in 2019, the last year before the pandemic.
Travel restrictions during the Covid-19 pandemic hammered the kingdom's vital tourism sector and arrivals have not bounced back as quickly as officials hoped.
Officials hopeto hit 35 million visitors in 2024, with a target of $55 billion in revenue.
