The bodies of six people have been found at a luxury hotel in central Bangkok.
Three men and three women were found dead in a Thai hotel room on Tuesday.
According to one version, the cause of death could have been poisoning, writes Sky News .
Thai Prime Minister Sretta Taweesin said four were Vietnamese and two were American citizens.
Police said the fifth-floor room was locked from the inside but there was no sign of a struggle.
The food delivered to the room was left untouched, but the drinks were consumed.
Police found that all six cups contained unidentified substances at the bottom.
The dead tourists were discovered by a maid after one of them failed to check out on time.
The case is being treated as a homicide given that one person is missing, police chief Sangsawang said.
The hotel rooms were initially booked for seven people.
