be necessary to establish as a criminal offence, when committed intentionally after the commission of any of the offences established in accordance with this Convention without having participated in such offences, the concealment or continued retention of property when the person involved knows that such property is the result of any of the offences established in accordance with this Convention. Article 25. Obstruction of justice Each State Party shall adopt such legislative and other measures as may be necessary to establish as criminal offences, when committed intentionally: (a) The use of physical force, threats or intimidation or the promise, offering or giving of an undue advantage to induce false testimony or to interfere in the giving of testimony or the production of evidence in a proceeding in relation to the commission of offences established in accordance with this Convention; (b) The use of physical force, threats or intimidation to interfere with the exercise of official duties by a justice or law enforcement official in relation to the commission of offences established in accordance with this Convention. Nothing in this subparagraph shall prejudice the right of States Parties to have legislation that protects other categories of public official. Article 26. Liability of legal persons 1. Each State Party shall adopt such measures as may be necessary, consistent with its legal principles, to establish the liability of legal persons for participation in the offences established in accordance with this Convention. 2. Subject to the legal principles of the State Party, the liability of legal persons may be criminal, civil or administrative. 3. Such liability shall be without prejudice to the criminal liability of the natural persons who have committed the offences. 4. Each State Party shall, in particular, ensure that legal persons held liable in accordance with this article are subject to effective, proportionate and dissuasive criminal or non-criminal sanctions, including monetary sanctions. 21