The relatives of two of the three American soldiers shot dead at a Jordanian air base last year described the pain of their loss in letters Monday to a military court trying the alleged killer.

The parents of one soldier and the sister of a second attended a court hearing in Jordan's capital, Amman and will remain until the verdict, expected next Monday.

The defendant, a Jordanian soldier, has pleaded "not guilty." If convicted, he faces life in prison. The U.S. military trainers were killed when three vehicles carrying four U.S. troops came under fire at the gate of an air base in southern Jordan in November.

The victims were 27-year-old Staff Sgt. Matthew C. Lewellen of Kirksville, Missouri; 30-year-old Staff Sgt. Kevin J. McEnroe of Tucson, Arizona; and 27-year-old Staff Sgt. James F. Moriarty of Kerrville, Texas.

Moriarty's sisters, Melissa and Rebecca, and Lewellen's parents, Charles and Cindy, described the pain of their loss in letters to the court.

They also criticized the Jordanian authorities' initial handling of the shooting, including claims that the U.S. troops had triggered the shooting by disobeying gate procedures. Jordan later withdrew such claims.

Rebecca, who was in court Monday, wrote that she and her siblings had exchanged messages the day before her brother's Nov. 4 death to plan a Thanksgiving get-together later that month.

Coping with the loss has been "utterly exhausting, especially when I feel that justice has not been served," she wrote.

"The initial days brought constant tears," she wrote. "My face swelled up and ached from so much crying. I couldn't taste food. Everything reminded me of him."

Melissa Moriarty, who is to arrive in Jordan this weekend, wrote that she has endured "extreme anguish and darkness" following the death of her brother.

A key issue during the trial has been the possible trigger for the shooting.

The defendant, 1st Sgt. Marik al-Tuwayha, has said he had heard a pistol shot coming from the direction of the U.S. convoy and that he opened fire because he feared the base was coming under attack.

Several gate guards testified that they heard a sound that might have been a pistol shot but that they held their fire because they couldn't identify the exact source.

The defendant has said he initially opened fire from inside a guard house where he was at the time, believing he was complying with rules of engagement. He has said he had "no intention of killing anyone" and felt no resentment toward Americans.

The prosecutor said Monday that the defendant acted with intent, having fired dozens of rounds over several minutes. He said the defendant did not comply with the rules of engagement because he did not determine the source of the alleged pistol shot.

In an interview Monday, Rebecca Moriarty and the Lewellens questioned why the court did not screen a security camera video of the incident and why it did not ask a surviving U.S. soldier to testify. They said the survivor was willing to take the stand.

"That is very disappointing to us as families but especially to him who went through it and is the only key eyewitness to what took place," said Charles Lewellen, 53.

The bereaved families said the surveillance video, shown to them by U.S. law enforcement, shows the defendant reloading and shooting at Americans who were waving their hands and yelling: "We're Americans! We're friendly."

Rebecca Moriarty said the shooting lasted for six minutes.

"The last word my brother said was 'friend,'" she wrote. "He spent the last six minutes of his life trying to defuse what was, at the very least, a misunderstanding."