The object of their outrage, former Pfc. Steven Dale Green, convicted of murder and rape, apologized and said he will face "God's justice."
In a hearing, surviving members of the al-Janabi family gestured and questioned Green, convicted earlier this month of killing four people in Iraq.
Hajia al-Janabi, the grandmother of two victims, tried to approach Green at the defense table. As federal marshals led her back to the gallery, she shouted: "I just want to see him. I just want to see him. You have no mercy."
Green, speaking publicly for the first time since his arrest nearly three years ago, told his victims' relatives that he will face "God's justice" after spending the rest of his life in prison. The statement came as part of a sentencing hearing for Green, 24, of Midland, Texas. The remainder of the hearing and formal sentencing are scheduled for Sept. 4.
Green faced the family and called the killings as "evil."
"When I die, I'll be in God's hands," Green said. "In the kingdom of God, there will be justice and whatever I deserve, I'll get."
A civilian jury convicted Green on May 7 of multiple counts, including conspiracy, rape and murder in the March 12, 2006, killings of 14-year-old Abeer al-Janabi and her father, mother and 6-year-old sister near Mahmoudiya, Iraq, about 20 miles south of Baghdad.
The jury failed to agree on a sentence, meaning he automatically receives life imprisonment without parole. He could have been sentenced to death.
Thursday's hearing normally would have been part of Green's formal sentencing later. But U.S. District Judge Thomas B. Russell allowed the al-Janabi family to speak to the court and Green without having to make another trip from Iraq.
Five members of the al-Janabi family condemned Green for the slayings, calling him a dog, a coward and a criminal. Several said Green should have received a death sentence.
"You are a bad stigma on your whole family," Ameena Hamza Rashid al-Janabi, Kassem al-Janabi's sister, said through an interpreter. "You are a stigma on your family and all your relations."
Two surviving sons, Mohammed al-Janabi and Ahmed al-Janabi, said they didn't understand why Green killed their parents and sisters.
"If my father was a terrorist, he would not have lived where the Americans were," 15-year-old Mohammed said through an interpreter. "Why did he kill my family?"
Mohammed, given a chance to address Green directly, stared at him for a few seconds, then declined to say anything.
Ahmed, whose age wasn't given, said his father was an innocent man who was enjoying time with family the day of the killings.
"I swear by God my father didn't do anything, didn't do anything," Ahmed said.
Mahdi al-Janabi, a family cousin who also goes by the name Abu Farras, referred to Green as a monster and said the jury should have imposed a death sentence.
"Abeer will follow you and chase you in your nightmares," he said. "May God damn you."
Green reading from a written statement, told the family he didn't go to Iraq intent on killing civilians and wishes "I could take it back and I can't." Green then apologized to Mohammed and Ahmed.
"I know what I did left a hole in their lives and scars on their minds," Green said. "And, there's no making up for that."
Defense attorneys Darren Wolff and Patrick Bouldin, said at a press conference Thursday that speaking to the al-Janabi family will allow Green to start dealing with what happened in Iraq.
"He's got a lot of stuff to contend with for the rest of his life," Wolff said.
Green had been assigned to the Fort Campbell, Ky.-based 101st Airborne Division. He was discharged from the Army in May 2006 with a personality disorder. Because he was arrested after being discharged, he was tried in civilian court.
Three other soldiers are serving extended sentences in military prison after being convicted or pleading guilty in courts martial. Those soldiers will be eligible for parole.
Bouldin and Wolff said they are still studying the case record, but plan to appeal the conviction and challenge the law that allowed Green to be tried in civilian court.