OSI

**Office of Special Investigations (OSI) – Military History** The United States Air Force Office of Special Investigations (OSI) was established on August 1, 1948, as a separate investigative agency modeled after the Federal Bureau of Investigation (FBI). Its primary mission is to conduct criminal investigations, counterintelligence, and specialized investigative activities to protect Air Force and Space Force personnel and resources. Over the decades, OSI has played a critical role in uncovering espionage, combating terrorism, and supporting contingency operations worldwide. Today, OSI operates globally, providing essential security and investigative support to ensure the integrity and readiness of the U.S. Air and Space Forces.