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A jury must now decide whether confessed Al Qaeda conspirator Zacarias Moussaoui is a calculating terrorist responsible for the deaths of Americans on Sept. 11, 2001, or an Al Qaeda lackey with delusions of grandeur who had nothing to do with 9/11.

The jury of nine men and three women in Moussaoui's death penalty trial resumes deliberations Thursday after receiving the case late Wednesday afternoon.

Lawyers for the two sides painted sharply divergent views of whether the 37-year-old Frenchman was responsible for any of the nearly 3,000 deaths on Sept. 11.

Prosecutor David Raskin told the jurors that Moussaoui's lies to investigators in the weeks before Sept. 11 killed Americans just as surely as if he had hijacked a plane and crashed it into the White House.

"The defendant's lies are as much a part of this plot as anything else. It's terrorist training 101," Raskin added. "Al Qaeda trains its people to lie: Don't give up the plot."

Moussaoui was arrested on Aug. 16, 2001, on immigration violations after his efforts to obtain flight training in Minnesota aroused suspicion. He lied about his Al Qaeda membership and his plans to hijack an aircraft and fly it into a U.S. target. Prosecutors contend that if Moussaoui had confessed, the FBI could have unraveled the plot.

"All Moussaoui had to do is say, 'I'm Al Qaeda,'" said prosecutor David Novak, and that would have set the FBI on its way to launching an all-out investigation and tracking down the Sept. 11 hijackers.

Defense attorney Edward MacMahon countered that it is incredible to assume "that the FBI would have transferred itself overnight into an institution that would have run a flawless investigation."

Trial testimony indicated that FBI supervisors essentially ignored the warnings of the FBI agent who arrested Moussaoui and quickly concluded that he was a dangerous Islamic terrorist.

The FBI "wouldn't have done anything, no matter what Moussaoui said or did" when he was arrested, MacMahon said.

Prosecutors countered that the government's performance prior to Sept. 11 is irrelevant to the jury's decision about Moussaoui's guilt.

"We're not here to tell you FBI headquarters did a good job," prosecutor David Novak said. The verdict form, he said, does not ask jurors to "grade the FBI (or) ... grade the CIA."

MacMahon also warned the jury that it cannot believe anything Moussaoui says, including his stunning admission in court that he was to have been a fifth pilot hijacker on Sept. 11. Moussaoui and his court-appointed attorneys have been at odds for years.

Moussaoui is trying to make himself look more important than he was, MacMahon said, and he suggested that Moussaoui may also be overstating his role to ensure a death sentence and obtain martyrdom through execution rather than spending the rest of his life in prison.

"He's trying to write a role for himself in history when, in reality, he's an Al Qaeda hanger-on," MacMahon said.

If this jury unanimously decides Moussaoui is eligible for the death penalty, it will reconvene to hear more testimony about whether to actually impose execution. That second phase would be a forum for victims of 9/11 and their families to testify about the impact of the attacks.

Unresolved is what occurs if the jury is unable to agree on eligibility. Defense attorneys say that would automatically result in a life sentence; prosecutors argue it should result in a mistrial, which would allow them to prosecute Moussaoui again.

Moussaoui pleaded guilty last April to conspiring with Al Qaeda to hijack aircraft and other crimes. The sentencing trial decides only his punishment: death or life in prison.

Moussaoui testified Monday that he was supposed to hijack a fifth jetliner on 9/11 along with would-be shoe bomber Richard Reid, although he has previously denied any role in 9/11 and claimed he was part of a separate conspiracy.

MacMahon noted that captured 9/11 mastermind Khalid Shaikh Mohammed and other top al-Qaida operatives had said in written testimony that Moussaoui had nothing to do with 9/11.

Prosecutors must prove that Moussaoui's lies caused at least one death on 9/11 for Moussaoui to be eligible for the death penalty.