It was not unexpected...on the eve of the 10th anniversary of 911, US Intelligence officials are probing details about a 'credible' tip about a terror attack.

The source, who has proved to be credible and reliable before, tipped US authorities off to a potential threat, possibly involving car bombs, that would coincide with the 10th anniversary of the 911 attacks.  Fox News reports officials are taking the information seriously.  From what was released, it seems to center around Washington D.C. or NYC, and possibly involve car bombs.  Intelligence says it could be as many as 3 individuals, who traveled from Pakistan in Mid August, and could involve plans to detonate car or truck bombs between Sept. 12 and 14th.  It is called a 'credible' but unprovable threat.   Documents found in the compound of Osama bin Laden showed plans to strike the US on the 10th anniversary of 911. Initially, anywhere from 2-4 Budget or Penske rental trucks were being sought in connection with the information tip, as potentially being involved, but KTLA News in Los Angeles reports these vehicle have been accounted for.