A veteran federal prosecutor who left DOJ last year, Tamm worked at OIPR during a critical period in 2004 when senior Justice officials first strongly objected to the surveillance program. Those protests led to a crisis that March when, according to recent Senate testimony, then A.G. John Ashcroft, FBI Director Robert Mueller and others threatened to resign, prompting Bush to scale the program back. Tamm, said one of the legal sources, had shared concerns about he program’s legality, but it was unclear whether he actively participated in the internal DOJ protest.

The FBI raid on Tamm’s home comes when Gonzales himself is facing criticism for allegedly misleading Congress by denying there had been “serious disagreement” within Justice about the surveillance program. The A.G. last week apologized for “creating confusion,” but Senate Judiciary Committee chair Sen. Patrick Leahy said he is weighing asking Justice’s inspector general to review Gonzales’s testimony.

The raid also came while the White House and Congress were battling over expanding NSA wiretapping authority in order to plug purported “surveillance gaps.” James X. Dempsey of the Center for Democracy and Technology said the raid was “amazing” and shows the administration’s misplaced priorities: using FBI agents to track down leakers instead of processing intel warrants to close the gaps. A Justice spokesman declined to comment.