MANILA - The Philippine National Police (PNP) in Eastern Visayas created a special investigation task group on Tuesday for the shooting incident that left Calbayog City Mayor Ronaldo Aquino and four other people dead.

• READ: Calbayog City mayor's vehicle ambushed; 3 dead, 1 in critical condition - PNP

In a statement, the PNP said the local chief executive's death is now subject of a "thorough investigation." Justice Secretary Menardo Guevarra separately instructed the National Bureau of Investigation to conduct a probe on Monday's incident.

SITG "Aquino" will be headed by Col. Edwin Wagan, deputy regional police director for operations, according to state media.

The police earlier claimed Aquino and at least 2 of his companions were killed in a shootout. Samar 1st District Rep. Edgar Mary Sarmiento refuted it, describing the incident as an "ambush."

"Details of the incident remain to be sketchy as initial findings of investigative units are yet to be fully consolidated by the newly-organized [special investigation task group]" the PNP statement read.

But it said the "exchange of gunfire" was between the camp of Aquino, and PNP personnel from its Integrity Monitoring and Enforcement Group, and Provincial Drug Enforcement Unit, who were conducting Red Teaming inspection in the area.

"The group of Mayor Aquino was alleged to have initiated the shootout when his close-in security fired at the unmarked vehicle of the IMEG-PDEU... that was travelling in the same direction along the road," the police said.

Quoting witnesses, Sarmiento said it was the police who shot first at Aquino's vehicle.

RELATED VIDEO:

Watch more in iWantv or TFC.tv

The incident that happened in Barangay Lonoy, Calbayog City also left Aquino's police escort and driver dead, as well as two from the side of the PNP, according to police.

A civilian employee from Aquino's camp, and one personnel from the national police were wounded.

The two camps' firearms will undergo forensic examination, the police said.

Not a subject of PDEU's operation

The PNP said the IMEG-PDEU denied Aquino was targeted or even a subject of their operations, but this would also be investigated by the SITG.

The police said the police operatives in the incident were "initially unaware" of the passengers inside the mayor's vehicle "that fired upon them."

"It was only after the firefight that the said vehicle was identified to be owned by Mayor Aquino. The same remains to be validated," said the PNP.

Aquino's death came more than a week after Vice Mayor Restituto Calonge of Mabuhay town, Zamboanga Sibugay was killed, and some 3 months after another mayor, Caesar Perez of Los Baños, Laguna, was fatally shot.

Calonge and Perez were both slain near their respective town halls.

• READ: Los Baños, Laguna mayor dies after being shot in town hall

On Sunday, 9 activists were also killed in alleged police raids in provinces south of Manila.

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