MANILA - Police on Wednesday said it was hunting down 5 suspects in connection with the killing of Fr. Richmond Nilo in Nueva Ecija over the weekend.

Nilo was about to start Mass at a chapel in Zaragoza town when he was shot dead by unidentified assailants on Sunday.

Surveillance cameras caught on tape 2 motorcycle-riding suspects in a road near the chapel moments before the crime, Central Luzon police director Chief Supt. Amador Corpuz told reporters.

Another CCTV footage, he said, showed a third suspect who served as lookout on board a motorcycle while 2 more cohorts were seen inside the group's getaway vehicle.

Corpuz said police are eyeing 3 possible motives behind Nilo's murder: his alleged involvement in a land dispute, his assistance to rape victims, and his supposed criticism of other religious groups.

PRO-3 Director C.Supt Amador Corpus: May 5 nang suspek na tinitingnan sa pagpatay kay Father Nilo sa Nueva Ecija | via @dzmmPatrol44 pic.twitter.com/JAXgFqHACJ

— DZMM TeleRadyo (@DZMMTeleRadyo) June 13, 2018

Nilo was the third Catholic priest shot dead by unknown gunmen in the last 6 months.

• 'Are you still clapping?' Lingayen clergy slam killing of Nueva Ecija priest

Unidentified assailants gunned down 72-year-old Rev. Fr. Marcelito Paez in Nueva Ecija last December, and Cagayan province's Rev. Fr. Mark Anthony Ventura in April.

Malacañang has vowed to resolve the killings, which it said had nothing to do with President Rodrigo Duterte's tirades against the Catholic Church.

• Duterte calls Catholic Church 'most hypocritical institution'

Sen. Risa Hontiveros has called for a legislative inquiry into the slays, noting a "pattern" in the incidents.

Filipino bishops have raised concern over Duterte's anti-narcotics drive, which has seen some 4,200 drug suspects killed after allegedly resisting arrest.

-- With a report from Henry Atuelan, ABS-CBN News