An unarmed Iraqi cooperated with American troops searching his house and said "USA good" minutes before he was shot to death, a former U.S. soldier testified Wednesday at his one-time squad leader's murder trial.

Jason Pizer testified that the Iraqi was alive with Army Staff Sgt. Shane Werst (search) when Pizer went to a translator to check the Iraqi's identification against a list of suspected insurgents.

Pizer said he radioed back to Werst to confirm the man was on the list. He said he then heard Werst say, "Expecting contact," and then the sound of gunfire. Pizer said he returned to the house and found Naser Ismail's body on the floor.

Werst, 32, is on trial on charges of premeditated murder and obstruction of justice in the January 2004 slaying of Ismail, which prosecutors say was in retaliation for a mortar attack that killed an Army captain earlier that day.

Werst could get life in prison without parole if convicted.

Defense attorney Capt. Mark Santos said in opening statements that Werst shot Ismail because the Iraqi lunged at Pfc. Nathan Stewart and reached for Stewart's weapon. He said Werst was following the rules of engagement because he thought Stewart's life was in danger.

Stewart testified Tuesday that Werst became enraged and repeatedly shot Ismail because he thought the man had lied about his identity. After the shooting, Stewart said, Werst pulled out a non-U.S. military gun, fired it at a wall and told Stewart to get the Iraqi's fingerprints on the weapon. Werst later reported Ismail had fired first.