WASHINGTON (AP) -- Attorneys for former White House aide I. Lewis "Scooter" Libby say the testimony of the government's first witness in the CIA leak trial may have been improperly influenced.

Marc Grossman, the former No. 3 official at the State Department, took the stand Tuesday and testified that in June 2003 he was the first person to tell Libby that one of the Bush administration's most vocal critics on Iraq was married to a CIA operative.

Foreshadowing a tactic he will use throughout the case, defense attorney Theodore Wells planned to attack Grossman's credibility. Grossman's memory is spotty and Wells believes his testimony may have been influenced by his former boss at the State Department, Richard Armitage. The night before Grossman spoke to the FBI, Armitage confessed that he was syndicated columnist Robert Novak's original source and was a subject of the investigation.

As Grossman continued to the cooperate in the probe, defense attorneys say, he went back to Armitage and told him what the FBI was asking and discussed his answers. Prosecutors sought to block Wells from inquiring about those conversations but U.S. District Judge Reggie B. Walton refused.