Eloy Pineda, campaign head of mayoral bet Chito Espino, nephew of Mayor Benigno Espino, was gunned down inside the barangay hall of San Juan Bano at about 8:30 a.m.
Senior Superintendent Rodolfo Mendoza, provincial police director, blamed the New Peoples Army (NPA) for the killing.
The mayor said Pineda was resting inside the barangay hall when three motorcycle-riding men barged in and shot him at least four times in the head with caliber .45 and 9-mm. pistols.
Espino declined to say if the killing was politically motivated. "What I know is that there are armed groups being reported in Arayat these days, although I dont know to which group they (the gunmen) belong," he said.
This town is considered one of the areas in Pampanga where the NPA and its rival rebel groups, the Hukbong Gerilya ng Arayat (Huks) and the Rebolusyonaryong Hukbo ng Bayan (RHB), are asserting their dominance.
Seven are vying in the mayoralty race here. Espino decided to retire from politics and fielded his nephew.
The other mayoral candidates include Vice Mayor Raul Quizon (Liberal Party), former mayor Nelson de la Cruz (Lakas-CMD) and former Huk leader Bon Alejandrino.