Manila: The defense may have strengthened the prosecution's case against Vice President Sara Duterte after using the same video evidence it could have attacked during cross-examination, former Far Eastern University (FEU) Law Dean Mel Sta. Maria said.
According to Philippines News Agency, the Senate impeachment court this week began taking up the Article of Impeachment involving Duterte's alleged threats against President Ferdinand R. Marcos Jr., First Lady Liza Araneta-Marcos, and former Speaker Martin Romualdez. Prosecutors presented video evidence and National Bureau of Investigation (NBI) testimony to authenticate the recording. Meanwhile, the defense cross-examined NBI Senior Agent John Mark Calilung on his testimony regarding the video evidence.
Sta. Maria highlighted that when a party wants to challenge digital evidence, the proper move is to attack the integrity, authenticity, and handling of the device or file itself. He emphasized that the defense should have questioned the credibility of the digital device by undermining its integrity and suggesting possible contamination.
Instead of challenging the video, the defense presented portions of the same video during cross-examination to provide context for Duterte's remarks. This move raised questions about their ability to dispute the video's authenticity. Sta. Maria noted that by using the video themselves, the defense inadvertently supported the prosecution's case.
He further explained that the prosecution's decision not to conduct a redirect examination after the defense used the video was strategic. The cross-examination may have already reinforced the prosecution's evidence.
Sta. Maria pointed out that it would be challenging for the defense to attack the video's integrity since the NBI had generated a hash value to verify the file's authenticity. The hash value, or digital signature, is sensitive to even the slightest alteration, making it difficult to claim the video was doctored.
The defense's cross-examination did not directly challenge the scientific and technological basis of the authentication process. Instead, they focused on attacking the motivation and political aspects of the affidavit.
Sta. Maria observed that the defense seemed to concede the existence of the statement, arguing it was protected speech or did not constitute an impeachable offense. He noted that this approach leaves the defense focusing on legal characterization rather than denying the statement itself.
On Facebook, Sta. Maria reiterated his assessment, citing a "justifying speech" by another defense lawyer, Mark Vinluan, as an attempt to contextualize Duterte's threat to the First Couple and Romualdez. He argued that failing to demonstrate through cross-examination that the video was doctored weakens the defense's position.
