The House Prosecution Panel is set to present Davao City Mayor Sebastian “Baste” Duterte as one of its witnesses in the ongoing impeachment trial against his sister, Vice President Sara Duterte.

Baste is among the public officials expected to testify on Article II of the impeachment complaint in the coming week, which concerns allegations involving Sara and her husband, lawyer Mans Carpio, and their alleged unexplained wealth.

House trial spokesperson Rep. Zia Alonto Adiong said Baste’s inclusion was not simply because of his familial ties to the Vice President.

Adiong said the mayor’s testimony would be material to Article II, particularly on business transactions involving Gencorp and Davao City.

Gencorp was among the business interests listed in Sara’s Statement of Assets, Liabilities and Net Worth, which was presented before the impeachment court on Tuesday, 15 September.

“Gencorp is not a random company. It is relevant because VP Sara herself declared a business interest in the company,” Adiong said.

Previous reports linked Gencorp to government transactions in Davao City worth ₱15.02 million from 2022 to 2025, including food and catering contracts.

Adiong said Baste’s testimony could help clarify the transactions, noting that prosecutors planned to present additional evidence involving the company.

“Mayor Baste was the leader of Davao City during the relevant period, so his personal and official knowledge may be relevant,” the lawmaker said.

Adiong stressed that Baste would appear as a witness, not as a respondent in the impeachment proceedings.

He said prosecutors wanted the mayor to tell the truth and were not necessarily seeking to have him incriminate his sister.

The lawmaker declined to disclose further details about the matters Baste would testify on, saying this could give the Vice President’s lawyers a roadmap of the prosecution’s presentation.

“What we will ask, what evidence he will be confronted with and what Mayor Baste will answer would be better off heard at the Impeachment Court,” he said.

Given Baste’s close ties to Sara and his presumed involvement in the transactions, Adiong said prosecutors may seek to have him declared a hostile witness.

A hostile witness may be subjected to leading questions by either the prosecution or defense.

Baste is expected to appear before the impeachment court on 23 September, subject to further changes in the court’s order.