I encourage you to take up some other hobbies if correcting the minor grammar errors of others is your passion now.
Have you tried hunting for arrowheads or other Indian artifacts in creeks or plowed fields? It is much better than seeking grammar corrections, as it yields valuable, hard assets that can be passed on.
You will have to file a freedom of information request with the agencies to get their evidence. I doubt you will be successful, as sources of classified information are protected.
I have something. Official conclusions of two government agencies.
If you want more than the conclusions, if you want the sources, then you are welcome to seek that. Just not from me. Seeking their sources is a fool’s errand.
I had a top secret clearance with access to special intelligence years ago. I respect their need to protect sources.