"Who introduced these trusties? And why is no action being taken against those who backed them?" he asked.The trustee arrangement emerged as a workaround after sanctions cut Iranian banks off from the global financial system. Oil minister Mohsen Paknejad has said the ministry's role ends with marketing crude, while the Central Bank oversees revenue deposits and transfers.The incident has raised uncomfortable questions about a system built on trust rather than formal safeguards. A system which has now cost the state billions.