The National Bureau of Investigation (NBI) will launch its own probe into the tense confrontation between its agents and Senate security personnel following the attempted serving of an International Criminal Court (ICC) arrest warrant against Senator Ronald "Bato" Dela Rosa.

NBI Director Melvin Matibag, in a radio interview on Wednesday, said the agency would not hesitate to discipline its own personnel if investigators find that agents crossed the line during the dramatic standoff inside the Senate on 11 May. 

“We will conduct our own fact-finding investigation.  If there were mistakes committed by our NBI agents, if they somewhat went overboard, we will not hesitate to discipline our ranks.” Matibag said in mixed Filipino and English. 

The confrontation erupted after NBI agents, who had earlier been cited in contempt by the Senate, attempted to leave the chamber, triggering a heated encounter with members of the Senate Office of the Sergeant-at-Arms (OSAA).

Matibag said the agents believed they were being unlawfully restrained, prompting a split-second law enforcement response.

“Of course, the NBI is a law enforcement agency, and the tendency is for them to interpret the situation as an attempt to illegally detain them, so they would arrest you instead. You would be the one brought in for investigation,” he said.

According to Matibag, one individual managed to break free during the commotion, ran, and fell on the stairs. He clarified that no punches were thrown despite the chaotic scenes.

“Then, when he managed to break free, struggled away, and started running, he fell on the stairs. There was no punching involved,” he pointed out. 

The NBI chief also said the bureau will coordinate with the Department of Justice (DOJ) on possible next steps regarding the ICC warrant.

The ICC earlier identified Senators Dela Rosa and Christopher Bong Go, along with former Justice Secretary Vitaliano Aguirre II, as among the alleged co-perpetrators of former President Rodrigo Duterte in the crimes against humanity case filed before the tribunal.

The ICC prosecutors said Duterte and his alleged co-perpetrators “shared a common plan or agreement to ‘neutralise’ alleged criminals in the Philippines (including those perceived or alleged to be associated with drug use, sale or production) through violent crimes, including murder” from at least 1 November 2011 to 16 March 2019.