Manila, Sept. 29 -- The Senate impeachment court on Tuesday declared Davao City Mayor Sebastian "Baste" Duterte a hostile witness in the impeachment trial of his sister, Vice President Sara Duterte, allowing House prosecutors to ask him leading questions about Davao City government contracts and other matters related to her alleged unexplained wealth.

Presiding Officer Sen. Francis "Chiz" Escudero ruled that prosecutors had established Mayor Duterte's adverse interest after he acknowledged his relationship with the Vice President, confirmed previous statements questioning the impeachment proceedings and admitted he would not have voluntarily testified without a subpoena.

"Court therefore declares that the adverse interest of the witness...