This according to NPR, among other sources.

In a move first reported by NPR, U.S. Attorney General Eric Holder said he has decided to drop the case against Stevens rather than continue to defend the conviction in the face of persistent problems stemming from the actions of prosecutors.

“After careful review, I have concluded that certain information should have been provided to the defense for use at trial,” Holder said in a statement Wednesday. “In light of this conclusion, and in consideration of the totality of the circumstances of this particular case, I have determined that it is in the interest of justice to dismiss the indictment and not proceed with a new trial.”