The fate of convicted terror conspirator Zacarias Moussaoui is in the hands of a jury in Alexandria, Virginia, just outside Washington. The jury must decide whether Moussaoui, the only person tried and convicted in connection with the 2001 terrorist attacks on the United States will be executed or sent to prison for life.
Both sides presented closing arguments in the penalty phase of the trial.
Prosecutor David Raskin said Moussaoui came to the United States to kill as many Americans as he could and that he lied to investigators with lethal intent after his arrest in Minnesota three weeks before the September 11 attacks.
The government maintains that Moussaoui deserves the death penalty because had he told what he knew about al-Qaida's attack plans, the FBI might have been able to unravel the 9/11 plot by tracing his links with some of the hijackers.
Defense attorney Edward MacMahon countered that his client was nothing more than an al-Qaida hanger-on and that he was not involved in the 9/11 plot, despite Moussaoui's claims to the contrary.
Defense lawyers have said previously that it would not have mattered what Moussaoui told officials after his arrest because the government missed so many potential leads leading up to the 9/11 attacks.
Legal analysts say Moussaoui hurt his chances of avoiding the death penalty when he testified on Monday that he was supposed to hijack a fifth airliner on September 11 and crash it into the White House.
Defense lawyers did produce testimony from al-Qaida leaders in U.S. custody who took issue with Moussaoui's claim that he was part of the 9/11 plot, arguing that he was not a reliable operative.
In another twist to the bizarre trial, it was revealed Tuesday that Moussaoui had offered to testify for the prosecution against himself in exchange for better jail conditions until he was executed.
The jury must first decide whether Moussaoui lied to the FBI after his arrest and whether those lies resulted in at least one death on September 11.
If the answer is yes, a second phase to the penalty trial will begin that will determine if the death penalty should be imposed.
The jury's only other choice is to sentence Moussaoui to life in prison without chance of parole.
Moussaoui pleaded guilty last year to six counts of conspiracy to commit terrorism. Three of those counts are punishable by death.
If the jury moves the penalty trial to a second phase, it is expected that relatives of some of the 9/11 victims will testify in court, a process that could take weeks.