Agent: Moussaoui 'could fly ... into the WTC'

Mueller admits FBI should have been more aggressive

Moussaoui has been indicted in federal court on six conspiracy charges relating to the September 11 terrorist attacks.

WASHINGTON (CNN) -- The head of the FBI told a Senate panel last week that an agent warned the bureau last summer that Zacarias Moussaoui, the first man charged in connection with the September 11 terrorist attacks, "could fly something into the World Trade Center."

FBI Director Robert Mueller admitted the bureau "should have more aggressively pursued warnings" from a Minneapolis-based agent about Moussaoui, a flight student and French national of Moroccan descent.

Mueller testified before the Senate Judiciary Committee, telling Illinois Democrat, Sen. Dick Durbin, he disagreed that the FBI "ignored a clear warning about ... September 11th by not responding properly" to the agent's memorandum.

In it, the agent "mentioned the possibility of Moussaoui being that type of person that could fly something into the World Trade Center," Mueller said.

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While admitting "the recommendations of the agent are something that we should have more aggressively pursued," the head of the FBI said, "I do not believe that it gave the signpost of that which would happen on September 11th."

Moussaoui has been indicted in federal court on six conspiracy charges -- to commit an act of terrorism, to pirate and destroy aircraft, to use weapons of mass destruction, to destroy property and to murder Americans. Authorities plan to seek the death penalty, although Moussaoui is not accused of killing anyone himself.

Prosecutors allege that Moussaoui underwent flight training in the United States and weapons training in an al Qaeda camp inside Afghanistan, like some of the 19 known hijackers, and received money from the same terrorist financier in Germany that the hijackers did.

Moussaoui's attorneys have said he had no direct connections to the hijackers who commandeered the four planes and crashed them into the World Trade Center, Pentagon and a rural Pennsylvania field, killing more than 3,000 people.

The defendant has taken an aggressive tack in his trial, asking for a new judge, making the motion that his court-appointed attorneys be fired and formally requesting that he not have to take court-ordered mental competency exams.

Moussaoui's trial is set to begin with jury selection on September 30, but experts expect the uncertainty surrounding his defense team will delay that plan.