The National Bureau of Investigation on Tuesday said the killing of Albuera Mayor Rolando Espinosa Sr. inside a sub-provincial jail in Leyte was a "rubout" that could be part of a much bigger conspiracy.

"After conducting an exhaustive investigation of the incidents surrounding the killing of Mayor Espinosa and Yap, the NBI concluded that the testimonies of several witnesses had disputed the claim of an alleged shootout between the [Criminal Investigation and Detection Group] operatives and inmates Mayor Espinosa and Raul Yap but a 'rubout,'" the NBI said in a statement on Tuesday.

Shootout or rubout? Espinosa photos tell 2 stories

The bureau issued the statement after revealing that it has filed multiple criminal charges against Supt. Marvin Marcos and police Criminal Investigation and Detection Group (CIDG) members in Region 8 for the death of Espinosa.

Based on the evidence, the NBI said "it is patently clear that the acts of the CIDG 8 operatives showed a community of purpose or an implied conspiracy."

"There was unison in their purpose and action, signifying that they were all moved by a single criminal intent," it said.

Espinosa and fellow inmate Yap were killed inside the Baybay sub-provincial jail in Leyte last November 5 after the mayor allegedly shot at police officers who were serving a search warrant.

But the NBI said there was "no indication" that the operatives who participated in the operation desisted or those who acted as lookouts prevented the team from shooting the victims.

It added that the warrant was "maliciously obtained" because the information or affidavit it was based on was perjured.

'WITNESS' DID

In an interview on DZMM Tuesday, NBI spokesman Deputy Dir. Ferdinand Lavin said the CIDG asset who testified to seeing Yap repack drugs inside his cell did not actually go to the jail based on evidence they gathered.

"Paano nila napaniwala ang korte na ganyan?" Lavin said, although noting they leave it to the judiciary to hold their own investigation.

[How did they manage to make the court believe they had cause?]

• READ: SC orders probe on judge who issued Espinosa search warrant

The NBI likewise said an operation dubbed "Oplan Galugad" executed on October 30 already made sure to rid of any contraband they were looking for.

"The same effort, however, yielded nothing but a few items like cellular phones. It was therefore, impossible for Espinosa and Yap to possess these firearms and illegal drugs inside their respective cells on the night of the supposed implementation of the search warrants," it said.

As for the gun recovered from Espinosa, Lavin said one inmate had testified to seeing an operative go inside the slain mayor's cell with a firearm and leave without it.

"Paglabas niya wala na yung handgun," he said.

[When he came out, the handgun was gone.]

Asked why the CIDG operatives would go through so much effort to get a warrant, the NBI official said he believes they wanted to use it as a "cover of legitimacy" while they execute their plan.

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Lavin, meanwhile, said morale remains high in the bureau despite President Rodrigo Duterte admission that he ordered Marcos reinstated as head of the CIDG-8.

"We believe in our investigation. We believe in the cause... the NBI has no ill motive to conduct the investigation. We are just doing our job," he said.