The National Bureau of Investigation (NBI) confirmed Tuesday that there was an attempt to harm a key witness in the impeachment case against Vice President Sara Duterte inside a Taguig City jail facility.

NBI director Melvin Matibag said in a television interview that a team of investigators was dispatched to the Bureau of Jail Management and Penology (BJMP) annex following reports that witness Ramil Madriaga had been confronted by another detainee.

Madriaga gained national attention in December 2025 after alleging that drug syndicates and Philippine Offshore Gaming Operators helped fund Duterte’s 2022 campaign. His affidavit, which claims he delivered large sums of money on Duterte’s instructions, was later cited in impeachment complaints filed in the House of Representatives.

“We sent a team to investigate. They found that there was indeed an attempt to harm him,” Matibag said, citing that investigators determined Madriaga had been cornered during the encounter.

Matibag said the circumstances of the incident were “puzzling,” as the other inmate involved had been transferred from a Pasay City facility on the same day the confrontation occurred.

“We called in Madriaga and also the detainee identified as the one who harmed him. Their accounts matched,” Matibag said. The NBI has since placed the identified inmate under stricter monitoring.

The witness’ lawyer, Raymond Palad, previously reported that the 3 March encounter at the Annex 2 facility prompted a reassessment of security. While the BJMP initially characterized the incident as a “minor misunderstanding” with no violence, the NBI has since deployed an officer to the facility to provide additional oversight.