Manila, April 19 -- The Philippine National Police (PNP) has ordered an impartial investigation into a viral EDSA Busway collision involving a police-marked vehicle and a public utility bus, amid questions about possible violations of standard operating procedures and the accountability of officers involved.

In a statement Sunday, PNP chief Gen. Jose Melencio Nartatez Jr. said they were verifying operational documents to establish whether the vehicle was properly deployed for official duty at the time of the crash.

"If this was not an emergency or a legitimate operation, then it's a clear violation of our deployment protocol. Walang special lane para sa mga pulis na walang (No official lane police officers who have no) official business...