The Office of the Ombudsman said senator Jose “Jinggoy” Estrada has been indicted for plunder and violating anti-corruption laws after he earned “kickbacks” amounting to ₱573 million (US$9.30 million) from a scheme that defrauded infrastructure projects paid for by the national budget.

“If the honourable court finds probable cause, we anticipate the subsequent issuance of warrants of arrest against the principal respondents,” Assistant Ombudsman and spokesman Mico Clavano told a press briefing.

Charged alongside Estrada are former public works minister Manuel Bonoan and engineering officials from the ministry.

Estrada did not immediately respond to a Reuters request for comment.

When asked by reporters on Tuesday about the impending charges, he said, “Well, if this is the price that I have to pay for standing on my own principles and what I believe in? So be it”.

The charges were filed on Thursday before the Sandiganbayan, which are special Philippine courts that tackle high-profile corruption charges.

They also investigated the ill-gotten wealth of the late president Ferdinand Marcos Sr.

The corruption scandal, which has centred on dangerously flawed flood-control facilities across the Philippines, has shaken the graft-weary nation and tempered economic growth in recent quarters.

Estrada has been jailed twice before, also on corruption offences.

His father, Joseph Estrada, was the first former president to be convicted of plunder.

His successor, Gloria Arroyo, later pardoned him and ordered his release, paving the way for his return to politics.