OSI BadgeWelcome to the official page of the Air Force Office of Special Investigations, DET 305, on McChord Field, Joint Base Lewis-McChord, Wash.

The Air Force Office of Special Investigations has been the Air Force's major investigative service since Aug.1, 1948. The agency reports to the Inspector General, Office of the Secretary of the Air Force.

AFOSI provides professional investigative service to commanders of all Air Force activities. Its primary responsibilities are criminal investigations and counterintelligence services.