In a DZRH interview, he said security measures remain in place.
“There’s an in-house security, the OSAA [Office of the Sergeant-at-Arms], there’s also the augmentation from PSPG [Police Security and Protection Group] from PNP, [and] there’s also the blue guards," he said.
Mendoza said authorities are investigating reports of armed individuals seen near the Senate who may be linked to the incident.
“The investigation with regard to the person’s identity is still ongoing,” he added.
He also said the Senate, the OSAA, the National Bureau of Investigation and other agencies present at the time are expected to cooperate in the inquiry.
Mendoza confirmed that Senator Ronald “Bato” dela Rosa remained inside the Senate overnight.
"He already slept,” he said.
He added that the Senate may convene for the impeachment trial on Monday or Tuesday.