THE National Bureau of Investigation (NBI) in Davao Region is now digging deeper into its investigation on the death of the Laak town Mayor Reynaldo B. Navarro, after the sacked Regional Intelligence Unit (RIU) head Senior Supt. Leonardo Felonia was linked to the ambush on May 28.

Davao City Mayor Rodrigo R. Duterte earlier revealed that a "mission order signed by said police official" was taken from the possession of one of the six armed men who attacked Navarro's convoy. Felonia was charged with murder for alleged involvement in killing the Cebu-based businessman Richard Lim King.

NBI acting regional director Lawyer Dante Gierran, in an interview, said he had already assigned some of his men to look for the suspects and closely monitor "persons of interest" who might have something to do in the killing of Navarro.

Amid their investigation, Gierran contacted and met on Thursday the RIU member SPO3 Eduardo Bajalia, PO1 Simplecio Samar, and retired police officer Diosdado Imelda, who were earlier accused by the New People's Army (NPA) to be among the "Big Four Logging Lords" in Southern Mindanao.

The rebels accused the so-called big four, including the late Navarro, of allegedly being involved in illegal logging activities in Davao del Norte, Compostela Valley Province, and Agusan del Sur, an accusation that Navarro earlier denied.

"Although charges were already filed at Davao del Norte [Provincial Prosecution Office] against the four suspects, who among the six attackers of the late mayor, there is a request from the family to conduct further investigation about the crime," Gierran said.

Gierran was quick to add that aside from the appeal of the family, the bureau also believe that someone tasked the suspects to kill Navarro, and it is their responsibility to look for the mastermind of the crime, who is still at large like the other four suspects.

When asked how Felonia was involved on the Navarro case, Gierran said the bureau is yet to investigate the matter. "This is an open fact finding investigation. As of this moment, I could not conclude anything yet," he added.

Members of the regional Special Investigation Task Group (SITG) under the Police Regional Office (PRO) 11 had already launched a manhunt operation against Joel Montenegro and three John Does, who were charged with murder earlier this month.

Davao PRO spokesperson Chief Inspector Jed Clamor, on the other hand, said their members are already investigating the accusations of the NPA against the three members of the "Big Four Logging Lords" here in Southern Mindanao.

Navarro, on board a white Montero Sport with the plate number SHE-663, was on his way to Tagum City when six armed men riding in two motorcycles attacked him upon reaching Kilometer 9 at Purok 12 in Barangay Sigayen in Asuncion town in Davao del Norte around 8:20 a.m.

Two of the attackers were killed when Navarro's security escorts retaliated. One of the attackers have a pending case of murder. The gun battle lasted for 20 minutes. The authorities recovered from the crime scene M16 and M4 rifles.

Gierran, on the other hand, said aside from Navarro's case, they are also digging deeper investigation on the death of King. He added that he already wrote a formal letter addressed to SITG, asking for copies of relevant documents on King's case.

In the official Facebook page of the Philippine National Police (PNP), since Felonia was relieved from his post in Davao City, the officer has to report to their mother unit, which is the Intelligence Group at Camp Crame in Quezon City.

Felonia was ordered relieved by Police Intelligence Group Director Diosdado Ramos last week, after he was tagged in the murder case of King, who was shot dead at Vital-C building in Barrio Obrero this city on June 12.