Baghdad, Iraq ? An American soldier charged in the rape and killing of a 14-year-old Iraqi girl and the slaying of her family told investigators that he and his comrades devised the attack while playing cards and drinking whiskey at a checkpoint, and that afterward he grilled chicken wings, a military investigator testified Monday.

The confession was revealed on the second day of testimony in a military hearing to determine whether the soldiers would face a court-martial. The March 12 killings in the southern Baghdad suburb of Mahmoudiya have enraged Iraqis and shamed the U.S. military.

Spc. James P. Barker, 23, told investigators in sworn statements that he and Sgt. Paul E. Cortez, 23, took turns sexually assaulting the 14-year-old, and that former Pfc. Steven D. Green, 21, also raped the girl after killing her mother, father and 5-year-old sister, military investigator Benjamin Bierce testified.

A fourth soldier, Pfc. Jesse V. Spielman, 21, was inside the house during the attack while another soldier, Pfc. Bryan L. Howard, 19, kept watch elsewhere, Barker told investigators, Bierce said.

The military tribunal, known as an Article 32 hearing, is similar to a civilian grand jury. After hearing from prosecutors and defense lawyers, an investigating officer will determine whether there is enough evidence for four of the soldiers to face a military trial on charges of rape and murder.

Another soldier from the same Army unit, Sgt. Anthony W. Yribe, is charged with failing to report the attack but is not suspected of taking part.

Green was discharged from the Army in May because of a “personality disorder,” according to court documents. He was arrested in North Carolina in late June and will be tried separately in federal court.

Bierce testified that Barker wrote in his sworn statement that he, Cortez, Spielman and Green had been playing rummy and drinking Iraqi moonshine mixed with an energy drink on the day of the killings.

“While they were playing cards and drinking Iraqi whiskey, the idea came to go to the Iraqi house, rape a woman and murder her family,” said Gary Griesmyer, another military investigator, who had interviewed Cortez.

Investigators testified that the attack lasted between 20 and 30 minutes, and that the soldiers hid their identities, hoping to pin the slayings on insurgents.

After the men returned to the checkpoint, Barker said he began to grill chicken wings.

Pfc. Justin Watt, who prompted the investigation, testified earlier Monday that he became suspicious of his friends and, through conversations with Yribe and Howard, pieced together what had happened.

Watt testified that Yribe told him that Green had admitted the attack to Yribe. Additionally, Yribe told Watt, a shotgun shell had been found in the house. The soldiers had taken rifles and a shotgun with them for the attack, investigators said.

Although many Iraqis have an AK-47 in their homes, shotguns are relatively rare.

“I wanted to see if I could confirm my suspicions that there were more people involved,” Watt testified. “I believed there were American forces involved.”