Somchai Poolsawasdi, director-general of the department, said that these importers understated freight rates or vehicle prices. They are among 60 importers, being investigated by the department for tax evasion.
The investigation followed a tip by the Office of Public Sector Anti-Corruption Commission. The commission also suspected the involvement of officers and politicians in the department in forging invoices.
Somchai said that initial investigation showed no involvement of politicians.