A US jury spared 9/11 conspirator Zacarias Moussaoui from execution, deciding he will spend the rest of his life in prison instead.

The jury did not reach the unanimity required for a death sentence.

However, the jury did agree unanimously that Moussaoui "knowingly created a grave risk of death" for more than the intended victims of September 11 and committed his acts with "substantial planning" - accepting two of the aggravating factors necessary for a death sentence.

But they did not give sufficient weight to those findings to reach a death sentence, balancing them against mitigating factors offered by the defence.

Jurors did not, however, accept defence arguments that Moussaoui was mentally ill.

Justice

Moussaoui said as he was led from the courtroom: "America, you lost." He clapped his hands.

US President George Bush said that the rejection of the death penalty for al-Qaida conspirator Zacarias Moussaoui "presents the end of this case but not an end to the fight against terror".

"Our cause is right and the outcome is certain: Justice will be served," the president said in a written statement minutes after the Moussaoui verdict was announced.

"Evil will not have the final say. This great nation will prevail."

Defence

In their successful defence of Moussaoui, his lawyers revealed new levels of pre-attack bungling of intelligence by the FBI and other US government agencies.

By the end of the trial, the defence team was portraying its uncooperative client as a delusional schizophrenic.

They argued he took the witness stand to confess to a role in September 11 that he never had - all to achieve martyrdom through execution or for recognition in history.

They overcame the impact of two dramatic appearances by Moussaoui himself - first to renounce his four years of denying any involvement in the attacks and then to gloat over the pain of those who lost loved ones.

Using evidence gathered in the largest investigation in US history, prosecutors achieved a preliminary victory last month when the jury ruled Moussaoui's lies to federal agents a month before the attacks made him eligible for the death penalty because they kept agents from discovering some of the hijackers.

Weeping

But even with heart-rending testimony from nearly four dozen victims and their relatives, which left some jurors wiping their eyes, the jury was not convinced that Moussaoui, who was in jail on September 11, deserved to die.

The case broke new ground in the understanding of September 11 - releasing to the public the first transcript and playing in court the cockpit tape of United 93's last half hour.

The tape captured the sounds of terrorists hijacking the aircraft over Pennsylvania and passengers trying to retake the jet until it crashed in a field.

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