The so-called “18 ex-Marines” will not attend Monday’s Blue Ribbon Committee hearing chaired by Sen. Erwin Tulfo after Senate President Alan Peter Cayetano formally advised them that the proceeding was not authorized by the Senate leadership and could not guarantee the protection accorded to witnesses.

In a letter dated 6 June addressed to the group’s lawyer, Levi Baligod, Cayetano acknowledged the former military personnel’s appearance before the Blue Ribbon subcommittee hearing last week and thanked them for their testimony despite what he described as the personal risks involved.

“We are deeply mindful of the courage and personal risk your testimony required, and we do not take that sacrifice lightly,” the letter read.

However, Cayetano categorically stated that the hearing scheduled for 8 June “was not authorized” by his office, by Sen. Pia Cayetano as Blue Ribbon Committee chairperson, or by Sen. Rodante Marcoleta as subcommittee chairperson.

“None of these offices scheduled such a hearing or authorized Director Josephine D.G. Herrera to issue any invitation in connection with it,” the letter stated. “The notice you received did not come from any of them.”

The Senate President stressed that only the Office of Sen. Pia Cayetano, the Office of Sen. Marcoleta, or the committee secretariat acting under their authority may issue official notices and invitations for Blue Ribbon proceedings.

The letter also cautioned the witnesses against participating in proceedings conducted outside the authority of the committee's designated chairpersons, saying the Senate could not assure them of the procedural safeguards normally afforded to witnesses.

“It is also our duty to caution the ‘18 Soldiers’ that we cannot assure them that any proceeding conducted outside the authority of the duly designated Chairpersons will afford the procedural safeguards and protection accorded to witnesses before properly constituted hearings,” Cayetano wrote.

The Senate chief also cited “recent threats of arrest directed at participants” and the involvement of several government agencies in matters related to the witnesses' testimony as reasons for urging caution.

“We therefore urge all concerned to exercise prudence and to verify the source and authority of any invitation purporting to compel their appearance,” the letter stated.

Cayetano emphasized that no witness summoned to testify should be subjected to threats or intimidation regardless of the committee's eventual findings.

“No person summoned to testify should face threat or intimidation, whatever the Committee's eventual findings may be,” he wrote.

The development effectively removes the key witnesses from Tulfo's scheduled hearing, escalating the leadership dispute that has split the Senate into rival factions claiming authority over the Blue Ribbon Committee.

The 18 ex-Marines previously testified before a Marcoleta-led Blue Ribbon subcommittee hearing, alleging they delivered suitcases of cash from flood-control kickbacks to President Ferdinand Marcos Jr., former House Speaker Martin Romualdez, Sen. Vicente “Tito” Sotto III, Tulfo and other government officials. They also claimed they worked as security personnel and couriers for fugitive former lawmaker Elizaldy Co.

All officials implicated in the allegations have denied the accusations, with Tulfo earlier describing them as baseless and warning that the witnesses could face libel charges.

Monday's hearing was expected to give the witnesses an opportunity to repeat their allegations under what the Gatchalian bloc considers the official Blue Ribbon Committee.