There is classified physical documentation that the IGIC is in possession of and has spent nearly four years verifying and found to be credible and corroborated

There is classified physical documentation that the IGIC is in possession of and has spent nearly four years verifying and found to be credible and corroborated by dozens of first hand witnesses over the course of their investigation. Unfortunately all of that is still classified but congresspeople who have been briefed have been sufficiently motivated to introduce legislation to investigate further (as Chuck Schumer has recently done in the Senate).