Photo credit: Mel Sta. Maria

The defense team of Vice President Sara Duterte may have unintentionally reinforced the prosecution's case after using the same video evidence it sought to challenge during the impeachment trial, according to former Far Eastern University (FEU) Law Dean Mel Sta. Maria.

Speaking in an interview on Bilyonaryo's On Point, Sta. Maria said the prosecution gained an advantage when the defense relied on the same video that prosecutors had already presented as evidence under Article IV of the impeachment complaint.

"But what is significant there? I think this is where the prosecution outsmarted the defense," Sta. Maria said.

The Senate impeachment court this week began hearing Article IV, which accuses Duterte of making grave threats against President Ferdinand Marcos Jr., First Lady Liza Araneta-Marcos, and former House Speaker Martin Romualdez.

During the proceedings, prosecutors presented video footage of Duterte's controversial statements along with testimony from National Bureau of Investigation (NBI) Senior Agent John Mark Calilung, who authenticated the recording and explained the process used to verify its integrity.

Sta. Maria said that if the defense intended to dispute the video, it should have questioned the authenticity and handling of the digital evidence itself.

"Because if you are to present a digital device, then you must attack that digital device. You must destroy its integrity."

Instead, he noted that the defense played portions of the same video during cross-examination to provide context for Duterte's remarks.

"So the question is, may issue pa ba ang authenticity, integrity, nung USB na iyon? Because they themselves showed snippets, right?"

He said using the same material makes it difficult for the defense to later question whether the video was authentic.

"Showed it, and made use of it as their evidence. So how can you say that that is not authentic when you yourself used it?"

Sta. Maria also pointed out that prosecutors no longer needed a redirect examination because the defense's own questioning may have further strengthened the evidence already presented.

He added that challenging the video's authenticity would be difficult because investigators generated a hash value, a unique digital signature used to determine whether a file has been altered.

"It will be very hard. Because they generated already what you call a hash value calculator."

According to Sta. Maria, even a minor change to a digital file would produce a different hash value, making alterations detectable.

He also observed that the defense focused more on issues surrounding the investigation and political motivations rather than the scientific process used to authenticate the video.

"And the cross-examination did not even touch on the science and technology of this thing. Ang inatake lang nila, you know, the motivation, the political, the affidavit."

Sta. Maria further said the defense appeared to acknowledge that Duterte made the statements but argued that they were protected speech rather than grounds for impeachment.

"At yung answer, hindi naman talaga nila sinasabing hindi sinabi yan. Ang sinasabi lang nila, 'It was an exercise of her freedom of expression.'"

He said that shifts the legal debate from whether the statements were made to whether they amount to an impeachable offense.

House prosecutor and Bicol Saro Party-list Rep. Terry Ridon echoed that view, saying the impeachment case is centered on Duterte's alleged threats—not on whether there was a "contract to kill," as some critics have claimed.

"Mahalaga maglinaw sa sinasabing wala naman pong impeachable offense dahil wala daw pong contract to kill."

"Hindi po contract to kill yung pinag-uusapan po rito."

Ridon said the central issue before the Senate impeachment court is Duterte's alleged threat against the country's highest officials.

"Ang pinag-uusapan po rito yung pong pagbabanta ng pangalawang Pangulo laban sa Pangulo, sa First Lady at sa dati pong House Speaker."

He cited the statement at the center of Article IV.

"Patayin mo si BBM, si Liza Araneta at si Martin Romualdez. No joke."

Ridon stressed that no individual, especially a high-ranking public official, has any justification for making threats against another person.

"Sa kahit saan man ho tayo magpunta, wala hong batayan para gumawa ng pagbabanta ang kahit sino man laban kahit kanino man."

He added that public officials are held to a higher standard because of the offices they occupy.

"Kaya mataas ho yung standard na pinag-uusapan ho natin kapag ka ho matataas na mga opisyal ng pamahalaan po yung gumagawa nito."

The prosecution maintains that the evidence presented so far lays the foundation for Article IV of the impeachment complaint, with additional witnesses expected to testify as the Senate trial resumes next week.