Senator Bam Aquino on Monday said he is looking at the possibility of filing cases against Justice Secretary Vitaliano Aguirre II after the justice chief tagged several lawmakers as the masterminds of the Maute group's rampage in Marawi City.

"Lahat ng insulto natanggap na namin, tinawag na kaming terorista... 'Pag tinawag kang terorista, it's really troublesome," Aquino told reporters.

"Dapat 'yun (mag-investigate) ang una niyang nagawa. Hindi 'yung makikinig siya sa fake news," he added.

But the senator said he will first confront Aquirre and hear his side when the Senate summons the justice chief to a congressional probe.

Aquino said his lawyers and advisers are still studying the circumstances of Aguirre's allegations and the senator's plan to sue the justice secretary in court.

The justice chief earlier alleged that Senators Antonio Trillanes and Bam Aquino, as well as Magdalo Party-list Representative Gary Alejano, and Ronald Llamas, political adviser of former president Benigno Aquino III, met with the Alonto and Lucman clans of Marawi City on May 2, three weeks before clashes between terror groups and government troops erupted.

Aguirre later recanted his allegations after it was revealed that the photograph he cited as evidence of the supposed meeting in Marawi City, which he showed to journalists in a press conference on Wednesday, was an image taken in 2015 at the Iloilo Airport.

• LOOK: Aguirre's 'evidence' to link minority lawmakers in Marawi crisis a 2015 photo

Still, he ordered the National Bureau of Investigation to investigate the possible involvement of opposition leaders in a purported destabilization plot against the Duterte administration.

• Aguirre to NBI: probe alleged destabilization plot by opposition leaders

The supposed destabilization plot of opposition lawmakers in Marawi City was not Aguirre's first gaffe.

In February, Aguirre drew flak for saying that "criminals are not humans" during a Senate hearing. He later on retracted his statement and shrugged it of as another misquote or grammatical error.

• 'Drug war isn't crime vs humanity': Aguirre says criminals not human

Weeks after, Aguirre committed another blunder by claiming that a so-called "Korean mafia" may be behind the abduction and killing of Korean businessman Jee Ick-joo.

The South Korean Embassy in Manila denied his claims, while both the National Bureau of Investigation (NBI) and the police neither denied nor confirmed Aguirre's allegation.

Police officers, not alleged Korean mafia members, have been charged for Jee's slay.

The Justice secretary also said that the wife of a "high-value" inmate at the national penitentiary was ambushed along Polaris Street, Barangay Poblacion, Makati City in February.

The Makati City Police however denied Aguirre's claims, saying they did not receive any reports of an ambush within the city.

- with a report from Sherrie Ann Torres, ABS-CBN News.