In a statement on Friday, the Central Investigation Bureau (CIB) said the suspects were detained after officers found three unclaimed suitcases containing drugs on a train travelling from Nong Khai in northeast Thailand to Krung Thep Aphiwat Central Terminal in Bangkok.

The CIB said the operation was carried out in coordination with the Thai railway authority and the highway police division as part of efforts to enhance passenger safety and curb crime on rail services.

“Officers on patrol on April 8 noticed three large black suitcases with combination locks placed on a luggage rack in one of the train carriages while passing through Khon Kaen province.

“Initial checks found no passengers claiming ownership of the bags, prompting further investigation,” the statement said.

CIB said railway staff later confirmed that three men had brought the suitcases on board at Nong Khai station, with CCTV footage identifying the suspects, who were later found seated in the same carriage.

“When questioned, the three men admitted transporting the luggage but claimed they were unaware of its contents, and that another party had asked them to deliver the suitcases to Bangkok.

“The suspects and the seized items have been handed over to investigators at Phon police station in Khon Kaen for further action”, the CIB said.