Manila, July 7 -- House of Representatives prosecutors on Tuesday asked the Senate impeachment court to issue subpoenas compelling Vice President Sara Z. Duterte's chief of staff, lawyer Zuleika Lopez, and National Bureau of Investigation (NBI) Director Melvin Matibag to testify in the impeachment trial.

In separate requests for subpoenas ad testificandum (to testify), the prosecution panel said the testimonies of Lopez and Matibag are "material, relevant and necessary" to prove Article IV of the Articles of Impeachment, which accuses Duterte of making grave threats against President Ferdinand R. Marcos Jr., First Lady Liza Araneta-Marcos, and former House Speaker and Leyte First District Rep. Ferdinand Martin Romualdez.

The prosecutor...