The latest word is that not only did Berger lose documents, but he also added some to the files:

...the thrust of the federal investigation now looking into Mr. Berger's actions should center not necessarily on what was taken from the archived files but what was placed in them.

Trying to rewrite a little history?

And this part is very disturbing, at least to me:

...adding an entirely new layer of intrigue to the story is word that telephone calls made by Berger during those latter two visits may have been monitored by an "unauthorized agency."

The National Archives stamps and signs all papers that you bring into their research rooms. However, usually they only stamp the last page and then staple the materials together. But they do look at the material, and I imagine that if it looks like an official document (i.e. similar to something that would be in their collection), they might stamp every page.

Of course, it was reported that he put materials into his briefcase, and he's not supposed to have one of those in a research room. I suspect that they were more deferential to the bigwig than they would have been to a regular person.

Back in the 1980s it was alleged that a UFO conspiracy theorist had actually planted fake documents in the National Archives in order to make a case that the government had covered up the existence of aliens. The documents were found to have been folded, as if someone had kept them in a pants pocket.

> a UFO conspiracy theorist had actually planted fake documents in the National Archives

Those were the "Majestic-12" or "MJ-12" documents. The forger made one minor error: he made them on 8.5 by 11 inch paper, but dated them 1947, when the government used only 8 by 10.