A reclusive oil merchant dominated Indonesia’s fuel trade for decades. Now he is embroiled in an $18 billion probe into the country’s state-owned oil producer that has become a litmus test for President Prabowo Subianto’s anticorruption drive.

Mohammad Riza Chalid, who has long maintained high-level political ties, is known in the industry as the "Gasoline Godfather” for his key role in importing billions of dollars of oil products, mostly from neighboring Singapore. His star has been waning — Indonesia wants to rely less on costly overseas purchases of gasoline or diesel — but he is the most audacious target to date for the current administration, as it reshuffles its energy procurement and attempts to supercharge growth in Southeast Asia’s largest economy.

Though Indonesia was an early member of OPEC, oil production has declined sharply in recent decades, falling almost 60% in the last quarter-century as fields age and investment falters, driving up its import bill. State oil-and-gas giant PT Pertamina has faced repeated criticism, including from Indonesia’s parliament, for its inefficiency. It is now being investigated for irregularities over the import of crude and oil products between 2018 and 2023 that authorities say have cost the state 285 trillion rupiah, or roughly $18 billion. The probe involves multiple companies, including at least one controlled by Chalid, according to statements made by the attorney general’s office.