Manila, July 9 -- 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.

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, with prosecutors presenting video evidence and National Bureau of Investigation (NBI) testimony on the authentication of the recording.

The defense, on the other hand, cross-examined NBI Senior Agent John Mark Calilung on his testimony authenticating th...