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MANILA - The son of slain Calbayog City Mayor Ronaldo Aquino said Monday he received death threats for pursuing investigation into his father's death.

"Meron nakarating sa akin na report, na isang pulis po na involved sa operasyon ng tatay ko ay nagsabi isusunod daw ako, para siguro ma-demoralize 'yong imbestigasyon," Mark Aquino told
ABS-CBN's TeleRadyo.

(I've received a report that a police officer involved in the operation said that I would be next, in order maybe to demoralize the investigation.)

The mayor was shot at least 21 times in Barangay Lonoy, Calbayog City on March 8 in what witnesses described as an ambush. The police initially described the incident as a shootout.

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The younger Aquino said that police officers involved in the incident were reportedly "in and out" of the police regional headquarters.

"Siyempre, nababahala rin po kaming pamilya, parte sa seguridad namin," he said.

(Of course, our family is worried, especially for our security.)

The Police Regional Office in Eastern Visayas has yet to comment on the allegation.

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The younger Aquino believed his father's slay was politically motivated.

The mayor was on his third and last term as local chief executive, and was planning to run as vice mayor in the 2022 elections.

"Sa nakikita ko po kasi, 'yong Calbayog is a vote premier distrito ng Samar. Sixty percent ng voting population ay galing sa Calbayog," the younger Aquino said.

(From what I saw, Calbayog is a vote premier in the district of Samar. Sixty percent of the voting population come from Calbayog.)

The police have formed a special investigation task group to probe the incident that left 6 people dead, including the mayor, even as the National Bureau of Investigation had also been tasked to look into it.

The other fatalities were identified as Aquino's close-in security detail Police Senior Sgt. Rodio Sario; his driver Dennis Abayon; Police Capt. Joselito Tabada; Police Senior Sgt. Romeo Laoyon; and Clint John Paul Yauder, a civilian.

The incident happened a day after police raids in provinces in the Calabarzon resulted in the death of 9 individuals, prompting some officials and groups to sound alarm over what they view as impunity in the country.

• READ: Robredo to Filipinos: Connect the dots, see 'web' that 'emboldens' killings

Malacanang condemned the Calbayog shooting incident, with Presidential spokesman Harry Roque expressing alarm as, according to him, it may be the start of killings due to politics as elections near.