Surat thani: The Department of Special Investigation (DSI) has summoned executives from eight shipping companies on suspicions of hoarding 60 million litres of diesel to exploit a sharp price increase.

According to Thai News Agency, investigators allege that 12 tankers intentionally delayed fuel deliveries to Surat Thani in late March, aiming to benefit from a government subsidy cut that led to a 6-baht-per-litre price hike. The DSI identified suspicious activities during 20 trips, including the disabling of GPS signals and ship-to-ship transfers conducted at sea.

"The investigation focuses on why these shipments were abnormally delayed," stated DSI spokesperson Woranan Srilum. "We are examining transport contracts and shipping manifests to determine if there was a deliberate attempt to profit from the energy crisis."

A representative from Big Sea Co Ltd, one of the implicated firms, appeared for questioning on Tuesday and pledged full cooperation with the investigation.

This probe comes amid increased scrutiny by Thai authorities on the energy sector, following regional supply concerns caused by the closure of the Strait of Hormuz.

Investigators are considering charges against the firms for "unreasonable delay in the distribution of controlled goods." Under Thai law, this offense could result in a maximum penalty of seven years in prison, a fine of up to 140,000 baht, or both.

The DSI aims to complete the collection of witness statements from the remaining shipping firms by April 23.