eign country might, for instance, work as a businessperson, a worker for a non-profit organization (such as a humanitarian group), or an academic. For example, the CIA's Ishmael Jones spent nearly two decades as a NOC. Many of the agents memorialized without names or dates of service on the CIA Memorial Wall are assumed to have been killed or executed in a foreign country while serving as NOC agents. In nations with established and well-developed spy agencies, the majority of captured non-native NOC agents have, however, historically been repatriated through prisoner exchanges for other captured NOCs as a form of gentlemen's agreement. Some countries have regulations regarding the use of non-official cover: the CIA, for example, has at times been prohibited from disguising agents as members of certain aid organizations, or as members of the clergy.[citation needed] The degree of sophistication put into non-official cover stories varies considerably. Sometimes, an agent will simply be appoi