A man and two women were found dead in a taxi parked at an LPG service station in Bung Kum district of Bangkok yesterday.
They were found at 8am in a pink taxi parked inside the station at kilometre marker 7 on Ram Intra Road.
The man, who was the driver, and a woman were found sitting in the front seats while another woman was lying in the back seat.
The driver was identified as Kathawut Jainoi, 26, of Roi Et, and the front-seat passenger as Janthima Ngarmbussakornsopon. Police named the woman in the back seat as Rattana Denwipaipana. The women were both 33 and from Chiang Rai.
Udon Wongsalee, 39, a car washer at the service station, said many taxis came to park at the secluded spot where Kathawut's taxi had parked.
Staff at the station saw the taxi park in the lot at 3am but said the driver did not get out of the car. Ms Udon said she saw three people sleeping inside the taxi with the engine running. At 7am, the station owner tried to awaken them by knocking on the car's window but failed.
Police officers from Khok Kram police station said all the bodies had bubbles of saliva coming out of their mouths and the cause of death was still being investigated. The taxi's engine was still on and its windows were open slightly when the bodies were found.
The vehicle, which has the Bangkok licence plate Tor Mor 7098, belongs to Pathumwan Taxi Cooperative. Acting Khok Kram police chief Sarawut Jindakham said the taxi had been parked with the engine on for many hours before police were alerted to the deaths.
Investigators suspect the taxi had travelled on a long journey before stopping at the station.
No one inside the vehicle showed any signs of a struggle or assault and no personal valuables had been stolen.
Initially, investigators thought the driver and passengers might have died from inhalation of toxic fumes from the taxi's exhaust pipe. However, the vehicle was not leaking LPG.
The bodies were taken to the Police General Hospital for forensic examination.