During the impeachment trial of Vice President Sara Duterte, her defense team questioned the credibility of National Bureau of Investigation (NBI) Director Melvin Matibag's testimony regarding alleged threats against President Ferdinand Marcos Jr.and other officials.

The prosecution presented Matibag as a key witness for Article IV of the impeachment case, which accuses Duterte of grave threats and an assassination plot.

However, defense lawyer Mark Vinluan challenged Matibag's personal knowledge of the NBI investigation, noting he only assumed his post in February 2026.Matibag admitted he based his testimony on existing records rather than direct involvement in the probe.

Defense lawyer Michael Poa further argued that Matibag's account of the first investigation lacks personal knowledge, classifying it as 'hearsay' under legal definitions.The defense emphasized that without firsthand experience, Matibag's testimony does not meet evidentiary standards.

This development highlights ongoing legal battles over the validity of evidence in high-profile political cases, raising questions about procedural fairness and the role of expert witnesses in impeachment trials.