Security officers from the Philippine Senate are being investigated for firing their weapons without provocation as a senator wanted by the International Criminal Court sought refuge in the building, officials said on Tuesday.

Senator Ronald dela Rosa briefly sought refuge in the Senate last week while asking the Philippine Supreme Court to stop an attempt by government agents to arrest him.

The fugitive senator, the former national police chief in the early years of Rodrigo Duterte’s anti-drug campaign, barely escaped arrest before wild scenes erupted on Wednesday.

Shots were fired during the mayhem that sent senators scurrying into their offices for shelter.

Philippine authorities presented their initial findings into the incident at a public briefing on Tuesday.

Interior Secretary Juanito Victor Remulla identified Senate Sergeant-at-Arms Mao Aplasca as the person who fired the first shot. Aplasca’s shot outside the building prompted a government agent to fire a warning shot in return, he said.