Members of the House prosecution panel questioned the continued opposition of Vice President Sara Duterte's defense team to opening a sealed box containing the tax records of Duterte and her husband, Manases "Mans" Carpio, ahead of the impeachment trial.

Lead House prosecutor Gerville Luistro said the defense opposed both the prosecution's request to mark the contents of the Bureau of Internal Revenue (BIR) box as evidence and its motion to formally mark the sealed box itself during the pretrial conference.

Luistro said the prosecution's request was based on the Senate impeachment rules requiring parties to pre-mark all evidence and identify witnesses they intend to present during the trial.

"That is why we registered our reservation as to the marking of the box, including its contents, because we understand that there's a rule that all the evidence must be pre-marked during the pretrial conference. Otherwise, we will not be able to present that during the trial," Luistro said.

Mamamayang Liberal Party-list Rep. Leila de Lima said the prosecution was puzzled by the defense's position because Duterte's camp had also listed BIR records among the evidence it intended to present, according to its pretrial brief.

"We really don't understand why they are making an issue out of not needing to seek permission from the impeachment court to open the box if both parties agreed, if the defense agreed to open the BIR box at this point," De Lima said.

Manila Rep. Joel Chua echoed the sentiment, saying the records should be disclosed if there is nothing to conceal regarding the allegations of unexplained wealth.

"If there is nothing to hide, let us just open the box. If their conscience is clear, then let us disclose the evidence," Chua said.

The Senate impeachment court formally concluded the five-day pretrial conference on 25 June after marking voluminous documentary evidence for possible presentation during the trial.

Luistro said the impeachment court gave the defense until 27 June to comment on several pending prosecution motions, including those involving the purpose of presenting similar witnesses, the use of Filipino and English during the proceedings, and the contested BIR box.

The sealed box was originally submitted during a House Committee on Justice hearing on 29 April in connection with allegations of Duterte's unexplained wealth, which were later included in the Articles of Impeachment.

The House panel opted not to open the box during its proceedings, believing the Senate, acting as the impeachment court, should determine whether its contents should be disclosed.

"We decided not to open because we believed in the power of the impeachment court. But even when it comes to the impeachment court, we are still struggling to open the BIR box," Luistro said.