Senior NBI agent first to testify against Sara Duterte

[Updated July 7, 2026, 3:32 p.m.]

MANILA, Philippines — A senior agent of  the  National Bureau of Investigation (NBI) took the witness stand on Tuesday as the impeachment trial against Vice President Sara Duterte entered its second day.

John Mark Calilung was presented by private prosecutor Amando Virgil Ligutan in connection with Duterte’s alleged threat to kill President Ferdinand Marcos Jr., his wife  Liza and former Speaker Martin  Romualdez.

READ: 2 NBI execs among first witnesses called to testify in Duterte trial

The allegation was contained in the fourth article of impeachment lodged against Duterte by the House of Representatives.

According to Ligutan, Calilung was part of the NBI Cybercrime Division team, which was tasked to  investigate  Duterte’s statements and threats against Marcos, Liza and Romualdez during an online media briefing on November 23, 2026.

It was in that particular briefing that Duterte claimed that she had hired someone  to  kill the three individuals.

At that point,  defense counsel Carlo Joaquin Narvasa interrupted the prosecutor to inquire if the latter was delivering a speech or an offer of testimony.

“May I object.  Is this a speech or an offer?” Narvasa asked.

“May I register my continuing objection,” he added.

Responding to this,  Ligutan told Narvasa to “please hold your horses.” 

The prosecutor continued, pointing out that Duterte’s assassination threats were publicly livestreamed and captured on video.

As the designated agent on case for the investigation, Calilung “personally conducted and participated  in the cybercrime and open-source investigation relating to the subject video and related digital recordings,” according to Ligutan.

In the course of its open-source investigation, the NBI found that the vice president had made other statements similar to the alleged threats against the president’s life, including her public remark that she had, at one point, thought about beheading the president of the Republic of the Philippines,” he said

The prosecutor added that, “In the course of  the  investigation, agent Calilung duly identified, preserved, collected, and authenticated the subject video and other related digital recordings.”

Aside from Calilung, the House prosecutors are also set to present another NBI agent as their second witness against the vice president also on the same topic. /mr