Metro Manila (CNN Philippines) — One of the findings of the National Bureau of Investigation (NBI) on the proliferation of illegal drugs at the New Bilibid Prison is that Senator Leila De Lima "brought about, supported, and even promoted the proliferation of illegal drugs for her political ambition."

De Lima is facing a new string of charges, including drug trafficking, qualified bribery, and graft, among others. This is the fourth criminal complaint against her filed before the DOJ.

Related: Alleged drug lord Jaybee Sebastian files charges vs. De Lima before DOJ

Aside from the senator, 17 more respondents were named in the complaint, including former DOJ Undersecretary Francisco Baraan, and former Bureau of Corrections Heads Francis Bucayu and Rafael Ragos.

The investigators said these former officials received huge sums of money from inmates, either directly or through their conduits.

De Lima's former aide Joenel Sanchez and former driver and bodyguard Ronnie Dayan were also charged.

The NBI doubts the defense of De Lima, who pointed out that she led the Bilibid raid last December 2014. It said the raid was either a legitimate operation or it was staged to make it look like she did something to curb illegal drugs inside Bilibid.

Convicts Jaybee Sebastian, Herbert Colanggo, Vicente Sy, Peter Co, Jojo Baligad, and Engelbert Durano — who all testified in the probe — are also charged despite the immunity granted to them by the Lower House.

NBI Spokesperson Ferdinand Lavin said on Thursday the inmates' immunity only covers instances where they incriminate themselves. But there were also named by other inmates as being involved in the illegal drug trade inside the national penitentiary.

The NBI is confident they have an airtight case against De Lima.

"We have interlocking confessions. Sanga-sanga itong confession. Yung sinabi nung isa vinalidate nung isa [What is said by one is validated by another]. Corroborated nung isa. We believe we have a good case," Lavin said.

Related: Ex-NBI officials tag former Justice Secretary as 'Mother of all Drug Lords'

He clarified the investigation doesn't end with the filing of cases, especially when it comes to the money trail.

"Tuloy-tuloy itong imbestigasyon [The investigation will continue]. As a matter of fact we may be called during the preliminary investigation to further bolster our evidence," he said.

Justice Secretary Vitaliano Aguirre said the four complaints against De Lima will be consolidated for a single preliminary investigation.

"I hope to send the subpoena to the respondents by tomorrow, at the latest Monday," he said.

De Lima: They won't quit until they destroy me

The senator said she is no longer surprised whenever the Duterte administration files "trumped-up" charges against her.

"Like their propensity for manufacturing lies, the filing of charges is fast becoming a bad habit for them. They just won't quit until they destroy me," De Lima said in a statement on Thursday.

De Lima said the evidence, including testimonies against her, were all fabricated.

She continues to stand by her innocence — saying she has nothing to do with the drug trade inside the Bilibid.

"NBI has based its charges has shown nothing but fantastic lies and fairy tales linking me to the drug trade. I repeat that I stand by my innocence because I only speak the truth," she said.