A US Army soldier has pleaded guilty to raping a 14-year-old Iraqi girl and helping murder her and her family.
James Barker agreed to the plea deal at the start of his court-martial in the US to avoid the death penalty, his civilian lawyer said.
A criminal investigation began in June into the killing of the family of four in their home in Mahmudiya, south of Baghdad, in March 2006.
Specialist Barker is one of four US soldiers charged with murder.
They are alleged to have helped a former private - who has since been discharged from the army - to plan, carry out and cover up the attack.
Two of the soldiers could face the death penalty if found guilty.
All four soldiers belong to the 2nd Brigade of the elite 101st Airborne Division.
Specialist Barker had agreed to co-operate with prosecutors and will testify against the others, his civilian lawyer, David Sheldon, said.
The others charged with rape and murder were Pte Jesse Spielman, Sgt Paul Cortez, and Pte Bryan Howard.
US troops have been accused of several abuses in Iraq
In addition, former soldier Steven Green has been charged in a civilian court and is awaiting trial in a Kentucky jail.
He was discharged from the army for a personality disorder earlier this year, and in July pleaded not guilty to charges of murder and sexual assault.