Philippine Senator Rodante Marcoleta was arrested on Monday morning, according to personnel of the Criminal Investigation and Detection Group.

An arrest warrant was issued the same day by the Third Division of the Sandiganbayan, the anti-graft court. The Philippine Office of the Ombudsman filed a plunder case against Senator Rodante Marcoleta before the Sandiganbayan on Friday.

According to the Ombudsman, Marcoleta allegedly received 75 million pesos (over $1.2 million) in undeclared campaign donations while serving as a congressman. The donations were allegedly not disclosed in the required 2025 Senate election and government filings.

From Tuesday to Thursday, crowds gathered in the Philippine capital, Manila, in support of Marcoleta, after the Ombudsman had earlier announced it would pursue a plunder case against him. Local police said the protest drew an estimated 15,000 participants at its peak.

According to local media reports, Marcoleta is considered an ally of Philippine Vice President Sara Duterte. He previously said the case against him is part of an effort to prevent him from participating in Sara's impeachment trial at the Senate, which will start on Monday afternoon.

The Senate currently has only 24 members. Senator Jinggoy Estrada surrendered to the police in early June, and the Sandiganbayan ordered his suspension from office over his graft case. Senator Ronald Dela Rosa is a fugitive wanted by the International Criminal Court, with his whereabouts unknown.