Senior Superintendent Dindo Espina, provincial police director, said the suspect, Cesar Sarmiento, was gunned down together with an unidentified companion in Barangay Anao.
Espina said Sarmiento and his brother Jesus, who was arrested earlier, were believed to have ambushed Masantol Mayor Peter Flores, his wife and two others in Barangay Bebe Anac, Masantol town last Feb. 12.
Flores and his driver sustained injuries, while the mayors police bodyguard, SPO4 Nicanor Yabut, was killed.
The Sarmiento brothers were charged with murder and frustrated murder in connection with the ambush.
Espina said Sarmiento was also implicated in the killings of barangay chairman Ismael Lampa last Jan. 6, Rey Panaligan last May 13, and Gerry Mercado last Aug. 16, all in Barangay Pandakaki, Mexico town.
Espina said a team of Mexico policemen, led by Chief Inspector Bernie Perez, spotted Sarmiento, together with a companion, on board an unlicensed motorcycle at about 3 p.m. last Thursday.
Perezs group, along with provincial and regional intelligence operatives, gave chase, cornering Sarmiento and his companion in Barangay Anao. Sarmiento fired at the policemen, triggering a 10-minute firefight, which left him and his pal dead.
Police found in Sarmientos possession a Galvinado caliber .45 pistol made in Spain, a Taurus caliber .45 pistol with live bullets, and an MK 2 grenade.
"Most criminals use motorcycles to commit crimes, so we are very strict in monitoring those without plates. So far, we have impounded at least 670 motorcycles," Espina said.
Meanwhile, in Apalit town, policemen led by Chief Inspector Fernando Gonzalez arrested last Thursday a group of suspected shabu dealers in Barangay San Vicente after month-long surveillance.
Arrested were Noel Benitez, Arnel Miranda, Ronald Manabat, and Grahambell Vergara.
Espina said the suspects were caught holding a shabu session in Benitezs house in Barangay San Vicente.
Seized from the four suspects were 101 plastic bags with shabu residue, five sachets of suspected shabu, two weighing scales, a tooter, two lighters, and four rolls of aluminum foil.
Charges of illegal drug use and possession have been filed against them.