I have been wondering about this.

WASHINGTON — The criminal probe into why former Bill Clinton aide Sandy Berger illegally sneaked top-secret documents out of the National Archives — possibly in his socks — has heated up and is now before a federal grand jury, The Post has learned. . . .

"It may have been off the front pages, but the investigation has been active," said a source with knowledge of the probe.

"[Berger] has been interviewed several times by federal agents — FBI and prosecutors."

Berger admits removing 40 to 50 top-secret documents from the archives, but claims it was an "honest mistake" made while he vetted documents for the 9/11 commission's probe into the Twin Towers attacks.

Berger has also acknowledged that he destroyed some documents — he says by accident. . . .

The documents include multiple drafts of a review of the 2000 millennium threat said to conclude that only luck prevented a 2000 attack.

That story conflicts with Berger's own testimony to the commission, in which he claimed that "we thwarted" millennium attacks by being vigilant — rather than by sheer luck, as the review reportedly suggests.