There are currently no public details on what evidence or documentation, if any, the whistleblower may have.
A former U.S. intelligence officer has claimed that the U.S. is secretly operating a UFO retrieval program and possesses "intact craft of non-human origin."
The whistleblower David Charles Grusch, who is a retired member of the National Geospatial-Intelligence Agency (NGA) and the National Reconnaissance Office (NRO), said that he was part of a task force that was established to identify what were once called "unidentified flying objects," or UFOS, and now officially known as "unidentified anomalous phenomena," or UAP.
As first reported by The Debrief, Grusch disclosed confidential information about these projects to Congress and the Intelligence Community Inspector General and subsequently filed a complaint that said that he suffered illegal retaliation for doing so. Notably, the article was written by Leslie Kean and Ralph Blumenthal, the reporters who broke the news of the Pentagon's Advanced Aerial Threat Intelligence (AATIP) program in the New York Times in 2017. That story kicked off the current resurging interest in UAPs in the government and among the public.
Grusch alleged that fragments of UAP have been recovered for decades by the government, its allies, and defense contractors. He said that post-retrieval analysis has determined that the fragments are "of exotic origin (non-human intelligence, whether extraterrestrial or unknown origin) based on the vehicle morphologies and material science testing and the possession of unique atomic arrangements and radiological signature."