Inside the government, some officials called her “Wayward Storm.” Her real name was Monica Elfriede Witt, an exemplary Air Force counterintelligence agent who had studied Persian and carried out covert missions in Iraq, Saudi Arabia and Qatar. But by mid-2013, Ms. Witt had become disillusioned with the government — why, exactly, remains a mystery — and had left the military. Thoughts of betrayal consumed her, federal prosecutors now say, until she finally acted on them at the Iranian Embassy in Kabul, where they say she “told all.”