Thread: How can I find out what office sponsored my security clearance investigation?

I have completed the application for my security clearance but now I need to sign and send some documents to the office that sponsored the investigation. I can't find the letter I was sent in the mail and that seems to be the only place the office name could be found. How do I find out which office sponsored me? This investigation is to update my US Army clearance.
I am no longer active duty. I must maintain my clearance in case I am called back to serve.

Your first stop should be your Commanding Officer. I worked for years for the DoD as a civilian and have a high level clearance. My investigation was completed by the DoJ, FBI and the CIA. Your CO should have an idea of where these investigations take place. After all, he/she would recieve any reports pertaining to your security clearance.