Mission (from AFOSI website)
The Air Force Office of Special Investigations provides professional investigative service to commanders of all Air Force activities. AFOSI identifies, investigates and neutralizes criminal, terrorist, and espionage threats to Air Force and Department of Defense personnel and resources. The command focuses on four priorities:
Detect and provide early warning of worldwide threats to the Air Force;
Identify and resolve crime impacting Air Force readiness or good order and discipline;
Combat threats to Air Force information systems and technologies; and
Defeat and deter fraud in the acquisition of Air Force prioritized weapons systems.
(Sounds pretty broad to me)
In theory, it is broad--in practice, AFOSI resources are rather limited (only a few officers per base). In cases of FOUO violations, counter-terrorism and counter-espionage, the AFOSI does run active investigations. For the most part, they are looking for crooked AF members who are trying to sell secrets or inside information. However, when dealing with non AF members or foreign nationals, they work closely with the FBI. Frankly, I don't see how these fraudulent documents fit in the four priorities outlined. It would be unprecedented for the AFOSI to try to prosecute a journalist under these circumstances. If you can demonstrate otherwise, you can ping me with an "I told you so" & I will happily admit my error.