MANILA, Philippines -- National Bureau of Investigation (NBI) Director Nonnatus Caesar Rojas said they are now looking for a third vehicle in connection with the alleged shootout in Atimonan, Quezon Sunday.

A white pick-up reportedly traveled with the two sports utility vehicles carrying the group of Vic Siman and Senior Supt. Alfredo Consemino, but managed to avoid the checkpoint set up by police officers in Barangay Lumotan in Atimonan.

The NBI said the missing vehicle, which allegedly carried around three to five passengers, may have clues that could shed light on the incident.

Thirteen men, including three policemen and a soldier, were killed in the shooting incident. -- Report from Jay Ruiz, ABS-CBN News; With ANC