The Department of Special Investigation (DSI) has issued a summons to a key suspect in a major fuel adulteration investigation, ordering him to report and hear formal charges on June 8.
A DSI source said Surat Sukcharoenkraisri, the younger brother of businessman Somboon Sukcharoenkraisri, known as "Sei Tue Cosmo", has been ordered to appear before investigators over alleged involvement in illegal fuel blending and overpricing linked to Trillion Petroleum Trading Co Ltd in Ang Thong.
The summons follows an expanded investigation into suspected manipulation of fuel quality and pricing within the wider supply chain after earlier charges were filed against the company and one of its registered directors. Mr Surat is scheduled to appear on June 8 to acknowledge the allegations.
The source said Mr Surat played a central role despite not being listed as a director or shareholder in company records. Financial and logistical analysis suggests he was closely involved in the firm's fuel distribution activities.
"Although his name is not listed in company documents, financial flows and other evidence indicate he exercised significant control over business decisions," the source said.
The investigation stems from allegations that fuel products were deliberately altered before being distributed for commercial sale, causing distortions in the domestic energy market.
The DSI is also examining 166 maritime fuel transport documents from six domestic refineries that allegedly failed to meet regulatory requirements, including incomplete shipment records.
