GUANTANAMO BAY NAVY BASE, Cuba -- With head bowed, Omar Khadr sat at his war crimes tribunal Thursday and heard about the hole he left in one American commando's family at age 15 when he hurled a grenade in war-torn Afghanistan and killed Special Forces medic Chris Speer.

"The victims,'' said widow Tabitha Speer, staring at the confessed war criminal, "they are my children. Not you. Their father was an honorable man. He was a good man. You will forever be a murderer in my eyes.''

For more than an hour Speer sat composed in a black dress and mostly described the pain of her 11-year-old daughter, Taryn, and emptiness of her son, 8, over the death of their U.S. Army sergeant dad from a July 2002 firefight near Khost, Afghanistan.

She read a note from the boy whose father stayed behind to see his 2001 birth, then left to join his elite unit hunting al Qaeda. "Omar Khadr should go to jail because of the open hole he made in my family,'' wrote Tanner. "Army rocks. Bad guys stink.''

She read a note from the girl, who shared his father's love of Elvis: "I'm mad at you for what you did to my family. My dad never got to see me play soccer or go to kindergarten.''

Then she looked 15-feet across the courtroom and glared at the Toronto-born 24-year-old who on Monday confessed to five war crimes in exchange for a plea bargain to support his transfer to Canada next year: "Everyone wants to talk about how he's the victim, he's the child,'' she said. "I don't see that.''

Throughout it all Khadr kept his head bowed, projecting what looked like a pose of contrition. At times he raised his eyes and met the widow's gaze but he sat stonily silent.

Prosecutors called Speer to help a military jury measure the loss before they mete out a sentence of up to life in prison for the murder of Speer, spying on U.S. troops and planting mines as an al Qaeda apprentice. Khadr's now dead father, Ahmed Said was an acolyte of Osama bin Laden who moved his family between South Asia and Canada.

Khadr's case had been condemned internationally by critics who said he was too young and should have been treated as a "child soldier.'' The United States picked him for prosecution, but spared him a death penalty case in consideration of his age, because his victim was an American soldier and because the Pentagon declared him an "unprivileged enemy belligerent.''

His victim's widow spoke with grace and eloquence, mostly unprompted by the lead case prosecutor, former Maj. Jeff Groharing, who has championed the case since the beginning.

To people who say that as a U.S. soldier, he and his family knew there was risks, she replied: "There are certain things in this situation that just aren't right.''

To a question from the jury of whether "this experience would be different'' if her husband was killed by an enemy soldier in an Iraqi or Afghan uniform, she said simple, "Yes.''

Thursday was the fourth day of the Khadr hearing.more testimony was expected in the afternoon and likely Friday morning before closing arguments and the jury is asked to deliberate a sentence.

In a nod to the war court's tricky logistics, Judge Patrick Parrish, an Army colonel, allowed the defense to jump in with a morning witness before the prosecution completed its side.

In a live video feed that broke just twice from Afghanistan, the Khadr team called a Naval officer, Capt. Patrick McCarthy, who served as the prison camps staff attorney for years, 2006-2008, to testify that given Khadr's youth and behavior in the prison camps since age 16 "he has rehabilitative potential.''