A former United States Air Force counterintelligence agent was charged with espionage after she defected to Iran and helped it target her former colleagues, the authorities said. In an extraordinarily detailed indictment made public on Wednesday, prosecutors disclosed that Monica Elfriede Witt, 39, gave the Iranians the code name and mission of a secret Pentagon program involving American intelligence operations. According to the indictment, she was working with members of Iran’s Islamic Revolutionary Guard Corps. The elite paramilitary group is known to carry out terrorist operations around the globe and has been sanctioned by the American government.