The Vice President is not immune from suit. He is an impeachable official but he is not immune from suit. Among the impeachable officials, only the President is immune from suit. Impeachability only means that he cannot be removed from public office except by impeachment. Any suit filed against him that would not result in his removal from office, like a civil suit for forfeiture of ill-gotten wealth, is allowed.
In jurisprudence, only the President, the State, and members of the diplomatic corps under international law, are immune from suit, for respective reasons. In the case of the President, he has to be protected from suits in order for him to concentrate on the business of running the government. He cannot be left attending to personal law suits left and right, instead of performing his job as the President. The State is immune from suit, and cannot be sued without its consent, under the principle that there can be no right against that which is the source of said right. Diplomats cannot be sued under the doctrine in international law that foreign envoys remain to be under the jurisdiction of their governments, not of the receiving state. This is a reciprocal privilege that is observed among countries with diplomatic relations with each other.
There is no doctrine in constitutional or political law that serves as a legal basis or rationale for immunity from suit of impeachable officials, other than for the President.
VP Binay is not the President, the State, or a member of the diplomatic corps representing a foreign state or government in the Philippines. Atty. Roque cites the case of former President Arroyo where he was prevented from filing a case for human rights violations against her. Precisely, President Arroyo was then the President. VP Binay is not the President.
Under the AMLA, the AMLC is authorized to file petitions for a freeze order or bank inquiry before the CA. In the case of a freeze order, the same shall be lifted if no case is eventually filed against the person who is the subject of the freeze order. The case to be filed need not be a criminal case for money-laundering. It can be a civil case for forfeiture of ill-gotten wealth, which is independent of a prosecution for a criminal case of money-laundering or its predicate crimes, such as plunder, graft and corruption, and malversation. According to Section 27 of the Rules of Procedure for Civil Forfeiture (A.M. No. 05-11-04-SC), "no prior criminal charge, pendency of or conviction for an unlawful activity or money laundering offense is necessary for the commencement or the resolution of a petition for civil forfeiture". In a civil forfeiture case, the degree of proof needed is only preponderance of evidence, not guilt beyond reasonable doubt.
After the freeze order and further examination of VP Binay's, and his relatives' and dummies' bank accounts, the AMLC can file a civil case for forfeiture of ill-gotten wealth through the Solicitor General. The filing, trial, hearing and decision in said case will not violate his impeachability since this civil case will only result in the forfeiture of his alleged ill-gotten wealth, not his removal from office.