MANILA - Sen. Teofisto "TG" Guingona III on Tuesday defended the powers of the Senate Blue Ribbon Committee to summon witnesses and resource persons to its hearings. This, after Justice Secretary Leila de Lima failed to present the whistle-blowers in Tuesday's Senate Blue Ribbon Committee inquiry on the scam. "I will not allow the powers of the Senate Blue Ribbon Committee to be diminished by anyone. The powers are found in the Constitution and upheld by jurisprudence," he said in a press conference. De Lima earlier told the Senate Blue Ribbon Committee that only the Ombudsman has jurisdiction over the cases filed by the Department of Justice. She said the Ombudsman has the authority to decide if the whistle-blowers can testify at the Senate while the Ombudsman is still doing preliminary investigation of the case. Guingona, however, disagreed with de Lima and said he will issue a subpoena to the justice secretary to present the whistle-blowers on Thursday. He also denied that he is fighting against the DOJ, saying that witnesses can still appear before the Senate inquiry even if a case is pending before the Ombudsman and the Sandiganbayan. "Hindi ko papayagan yan under my watch," he said.