Jurors at the trial of al-Qaeda plotter Zacarias Moussaoui have retired to consider their verdict on whether he should be executed or jailed for life.
Moussaoui has said he wished it was 11 September every day
The prosecution has called for the death sentence, arguing that "there is no place on this good Earth" for him.
Defence lawyers say the Virginia jury should give him "the long, slow death of a common criminal" in prison, rather than martyrdom through execution.
Moussaoui is the only man prosecuted in the US over the 9/11 attacks.
The judge will be bound to hand down the sentence chosen by the jury, which sat through six weeks of testimony.
Judge Leonie Brinkema congratulated both prosecution and defence lawyers on their handling of the case.
"There has probably never been a defendant as difficult as this one... he will probably never appreciate the efforts you have made," Judge Brinkema told Moussaoui's defence team.
As he left the courtroom, Zacarias Moussaoui turned to the public gallery, raised his hands in the air and clapped loudly.
Moussaoui's mother has said she will travel to the US from her home in France on Tuesday for the jury's decision.
Aicha el-Wafi "wants to be there for that moment, despite all the pain she feels", her lawyer Patrick Baudouin told the Associated Press news agency.
"It is the culmination of the trial," he added.
Pain and emotion
Defence lawyers, with whom Moussaoui refused to co-operate, have tried to avoid the death penalty by portraying the 37-year-old Frenchman of Moroccan descent as mentally ill.
The defendant rejoices in all that pain - he told you that himself
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Prosecutors say Moussaoui withheld information that could have helped prevent the 2001 attacks, in which about 3,000 people died.
They have tried to show the effects of the attacks using the emotional testimony of people affected by them as well as video and audio evidence of the day's events.
Addressing the jury, prosecutor David Raskin made great play of Moussaoui's apparent delight at the attacks and his refusal to show any signs of remorse.
"The defendant rejoices in all that pain. He told you that himself," Mr Raskin said.
The jurors heard the cockpit tape from the Pennsylvania plane
Prosecution evidence included a man talking on his mobile phone as the towers of the World Trade Center collapsed and the cockpit tape of the plane that crashed into a Pennsylvania field.
In his summing up, defence lawyer Gerald Zerkin said Moussaoui's contempt for the victims and the trial "is proof that he wants you to sentence him to death".
Mr Zerkin said the jury could instead "confine him to a miserable existence until he dies and give him not the death of a jihadist... but the long slow death of a common criminal".
Under cross-examination, Moussaoui said he had "no regret, no remorse" and wished it could be 11 September every day.
Although Moussaoui was in jail at the time of the attacks, on immigration charges, prosecutors say he told lies to allow the plot to continue.
The defence has tried to use this argument to its advantage, arguing Moussaoui is a liar who wants to claim an undeserved place in history.
Moussaoui was arrested in August 2001 at a flight simulator school in Minnesota.
During the trial, Moussaoui said he had been due to fly a fifth hijacked plane into the White House helped by jailed British "shoe bomber" Richard Reid.
Defence lawyers presented FBI evidence that it was "highly unlikely" Moussaoui and Reid co-operated on the 9/11 attacks.