Pol Col Theeradej Thammasuthee, chief of the CSD’s Sub-division 6, said an investigation team led by his deputy, Pol Lt Col Jirapong Rujiradamrongchai, will question the passengers who lost their mobile phones and money while they were sleeping as well as all railway staff on board the train.
The team will report the progress in the probe later once they have gathered information from the people involved, he said.
Investigators at Hat Yai Railway Police Station said they had questioned all six staff on duty on the train and found nothing suspicious. The six had good work records and urine drug tests had come back negative.
The State Railway of Thailand (SRT) had temporarily suspended the six employees until the investigation is completed.
Hat Yai railway police said the incident was a common case of theft and they had found no evidence to suggest the passengers had been drugged as some victims had assumed.
The passengers who lost their belongings had filed complaints with police in their hometowns, authorities said.
Somsak Mathipikai, an attendant in sleeper car No.10 in which the thefts took place, said there were a total of 32 passengers in the carriage when it left Bangkok on Monday afternoon.
The train picked up passengers at Prachuap Khiri Khan station, its last stop, and continued to the destination. He patrolled the car and toilets and checked the number of passengers but did not find any irregularities. Mr Somsak said he locked the car’s doors and went to sleep at a point between the carriages.
He woke up at 5am Tuesday when the train reached Surat Thani province only to learn passengers’ mobile phones and cash had gone missing.
He insisted no one had entered or exited the carriage after he locked the doors.