Related Rule
United States of America
Practice Relating to Rule 69. Loss of Inviolability of Parlementaires
The US Field Manual (1956) states: “The parlementaire loses his right of inviolability if it is proved in a clear and incontestable manner that he has taken advantage of his privileged position to provoke or commit an act of treachery.” 
United States, Field Manual 27-10, The Law of Land Warfare, US Department of the Army, 18 July 1956, as modified by Change No. 1, 15 July 1976, § 466.