Four years ago, the federal government arrested Zacarias Moussaoui, 37, for the 9/11 terrorist attacks. There were plenty of twists and turns in the trial, including delays caused by federal attorneys’ misconduct in coaching witnesses.

Although Moussaoui was sitting in jail on Sept. 11, 2001, during the trial he admitted allegiance to Osama bin Laden. He fought with his own lawyers. His behavior and statements were often provocative and erratic.

In the end, the prosecution failed to convince a jury that Moussaoui should get the death penalty. After 41 hours of deliberation, the jury sentenced him to life in prison.

Nine of the 12 jurors regarded Moussaoui’s troubled childhood, which included abuse by his father, as an extenuating factor. Three jurors wrote that Moussaoui had “limited knowledge of the 9/11 attack plans.”

Nearly 50 families of 9/11 victims testified, 36 for the prosecution and — remarkably — 12 for the defense. They testified “as citizens of a free nation, uncowed by terrorism,” said defense attorney Edward B. McMahon Jr.

Antonio Aversano’s father Louis died in the World Trade Center. After the sentence was announced, Aversano, who had testified for the defense, said, “Our best personal defense against terrorism is to not let the fear and hatred of terror consume our lives but to take whatever steps necessary to reclaim our hearts, to honor each other and to live life well.”

Andrea LeBlanc’s husband Robert was a passenger on the second plane that smashed into the World Trade Center. “Violence takes many forms and killing another human being will never undo the harm that has been done,” she said. “Killing Zacarias Moussaoui would not have helped us understand those things that lead to 9/11. Nor would it have helped create the kind of compassionate world I want to live in.”

Moussaoui will serve his sentence at the super-maximum security prison in Florence, Colo.