A day-by-day account of the Zacarias Moussaoui's sentencing trial, summarising the key events and testimonies presented by the defence.
THURSDAY 20 APRIL
Summary: The defence completes the presentation of its argument that Moussaoui is mentally ill and should therefore not face the death penalty.
Key witnesses: More relatives of 9/11 victims are presented who oppose the death penalty for Moussaoui. One, Marilynn Rosenthal, who lost her son Josh in the attack on the World Trade Center, says her family does not want to "get caught in a whirlpool of sadness and anger".
Also presented is a statement based on interviews with "shoe-bomber" Richard Reid and written by FBI analysts saying there is no evidence to back Moussaoui 's claim he planned a 9/11 attack with Reid. The defence use it to back claims Moussaoui is mentally ill.
WEDNESDAY 19 APRIL
Summary: The defence continues to present witnesses to support its argument that Moussaoui is mentally ill and should therefore not face the death penalty.
Key witnesses: Psychologist Paul Martin, a cult specialist, says French-Moroccans like Moussaoui generally feel alienated from Western society.
Dr Martin says Moussaoui's state of mind suffered further when he left France in 1992 to study in London.
Two relatives of 9/11 victims testify for the defence. Robin Theurkauf, whose husband, Tom, was killed, says "the Bible attempts to explain that we are all sinners, all broken people, but all children of God and loved by God".
Psychiatrist Michael First says Moussaoui's schizophrenia manifests itself through
paranoid delusions and disorganised thought and speech.
TUESDAY 18 APRIL
Summary: The defence continues presenting its argument that Moussaoui is mentally ill.
At one point, Moussaoui shouts out "beautiful terrorist mind", apparently in reference to remarks made by psychologist Xavier Amador on Monday, about the case of mathematician John Nash, a schizophrenic whose life story was made into the film, A Beautiful Mind.
Key witnesses: Mr Amador testifies for the defence that he is convinced Moussaoui is a paranoid schizophrenic who suffered from delusions before 9/11.
He says the defendant is convinced that US President George W Bush will free him from prison and that his court-appointed lawyers are in a conspiracy to kill him.
MONDAY 17 APRIL
Summary: The defence says Moussaoui came from a broken home where his mother was repeatedly beaten, and that there was a history of mental illness in his family.
Key witnesses: Behavioural specialist Jan Vogelsang testifies that Moussaoui had been in and out of orphanages during the first six years of his life and, as a teenager in France, was rejected by the family of his long-term girlfriend as a "dirty Arab".
Ms Vogelsang says Moussaoui's mother was physically abused throughout her pregnancies, including six before Moussaoui was born.
Moussaoui's sisters, both battling mental illness, testify on video that their brother was once a "sweetheart" who believed in the redemptive power of love.
Prisoner guard Vikas Ohri says he saw Moussaoui talking to himself in an apparent attempt to prepare himself to testify.
"He envisioned 9/11 happening in a dream. He envisioned himself getting captured, he envisioned getting freed by President George W Bush," he says.
THURSDAY 13 APRIL
Summary: The defence begins its case for a life sentence for Zacarias Moussaoui, arguing that he had a limited role in the attacks, he is mentally ill and execution would only fulfil his dream of martyrdom.
Moussaoui takes the stand for two-and-a-half hours of defence questioning and cross-examination by the prosecution.
He accuses his court-appointed lawyers of "criminal non-assistance", saying they had a "vested interest" in keeping the case and had failed to act in his best interests.
He tells the court he has no regret for the 9/11 attacks, and says he wishes "there would be more pain".
Key witnesses: Former prison officer James Aiken takes the stand before Moussaoui as an expert witness to counter prosecution arguments that he would remain a danger if kept alive in prison.
He says Moussaoui would be living in a "security bubble" and would gradually deteriorate if sentenced to life without parole.