MANILA - (UPDATE) Investigators are looking into 3 possible motives in the broad daylight assassination of a mayor in Nueva Ecija province, the second such killing of a local official in 2 days, police said Tuesday.

Mayor Ferdinand Bote of General Tinio town and his driver were leaving a government office in the capital of Nueva Ecija when motorcycle-riding gunmen approached his vehicle and shot him repeatedly on Tuesday.

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The possible motives in the killing have to do with local politics, Bote's quarrying business, and government projects allegedly connected to his separate construction business, said Central Luzon police director, Chief Supt. Amador Valera Corpus.

Corpus did not give additional details about the 3 angles, but said that a special investigation task group has been formed to focus on the 57-year-old mayor's killing.

He added that there are no reports connecting the mayor with the illegal drug trade.

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Surveillance footage, he said, showed 2 or 3 gunmen may have been involved in the assassination of Bote, who was known for going around without his bodyguards.

The slain mayor also doesn't have any death threats that the police are aware of, Corpus said in a press conference on Wednesday afternoon.

An autopsy of Bote's remains was conducted Wednesday morning, Corpus said, but refused to give details.

Corpus said he has ordered additional checkpoints and has deployed 200 additional policemen across the province to tighten security.

On Monday, Mayor Antonio Halili of Tanauan, Batangas was gunned down by a sniper while singing the national anthem at the weekly flag-raising ceremony in city hall.

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President Rodrigo Duterte said the 72-year-old mayor, who had gained prominence for parading drug suspects in the streets, may have been involved in drugs. He said Halili may have used his "walk of shame" campaign to convince authorities that he was not dabbling with narcotics.

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At Halili's wake, his daughter Angeline said Duterte had been misinformed in linking her father to the drug trade.

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Police have killed some 4,200 people in the anti-narcotics campaign since July 2016, with another 2,500 suspected drug suspects killed by unknown assailants over the same period.

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Human rights advocates said the victims were executed by the police, who have denied the accusations, saying the killings were done in self-defense.

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With a report from Reuters