HANOI, Vietnam (AP) — Vietnamese police have officially started investigating a former chief executive of state-owned energy giant PetroVietnam amid a widened crackdown on corruption.

The Ministry of Public Security says police also placed Phung Dinh Thuc under house arrest. Thuc is suspected of violating state regulations in his role at a thermo power plant.

On Tuesday, police ordered the prosecution and house arrest of Phan Dinh Duc, a board member of PetroVietnam, on the same charge.

Scandal-hit PetroVietnam has been in the center of a sweeping high-level anti-corruption crackdown over the past two years with more than 20 of its senior executives on trial or under investigation.