An Army sergeant who shot an unarmed Iraqi insurgent testified Wednesday at his court-martial that he was following the rules of engagement because the man was a threat.

After testifying for more than three hours, Sgt. Leonardo Trevino said he was innocent of premeditated murder, covering up a crime scene and other charges stemming from the June killing after a firefight in Muqdadiyah, Iraq.

Trevino testified that after following a trail of blood into a house, he thought the severely wounded insurgent was a threat because the flailing man might have been trying to trigger an explosive.

Trevino said that during the chaotic scene someone yelled that the Iraqi had or was reaching for a gun, so Trevino shot him.

He then asked where the Iraqi's gun was, and one soldier pulled out a gun and placed it on the floor, he said. But Trevino testified that he was disappointed that the soldier was implying they had to cover something up and gave him the gun back.

Pvt. Tristan Miller — a soldier on Trevino's small-kill team who went to a village overrun with Al-Qaeda insurgents in Muqdadiyah that night last June — previously testified for the prosecution that after soldiers killed one insurgent in the street, they followed the blood and found the insurgent in a house.

He said Trevino shot him in the abdomen, then motioned for another soldier to place a gun beside the man before telling both soldiers, "This is the story. This is the story: The man had a gun," Miller said, quoting Trevino.

A medic also testified earlier that Trevino ordered him to suffocate the insurgent, which the medic said he pretended to do, and that after learning the man was still alive, Trevino shot and killed him.

Trevino told a different story Wednesday. He testified that after a medic arrived and said the insurgent was about to die, Trevino said, he scoffed at the medic's suggestion of suffocating the man. He then left the house to give a report to his superior.

When Trevino returned, he said, he saw the insurgent's arm jerk, then fired his gun a second time as a reaction without aiming or looking at the man.

Trevino, a 1st Cavalry Division soldier from San Antonio testifying on the first day of the defense case, could face life in prison if convicted of premeditated murder, attempted murder, obstruction of justice and solicitation to commit murder.

Asked by his attorney whether he committed those crimes, Trevino said, "No, I did not."

Trevino acknowledged Wednesday that the insurgent did not have a pistol, but he said he wasn't worried when questioned by Army investigators "because all those shots were legit."

Mickey Nogle, a special agent for the Army's Criminal Investigative Division, testified earlier about his three long interviews with Miller.

Nogle said Miller never told him or wrote in his statements that he knew the insurgent was unarmed because he kicked a pillow off the man's arm — something he had told jurors. But under cross-examination, he said Miller stated several times that the insurgent was not a threat.

"We needed to know what kind of threat level they were under by the insurgent in that room," Nogle told the military jury.

Two soldiers testified that they believed Miller was untruthful. Another medic, Spc. Buddy Stratton, testified that another soldier who later turned Trevino in appeared to fake heat stroke symptoms after Trevino ordered him to do exercises as punishment for some infractions.

Spc. Stephen Patterson testified that he took pictures of the two insurgents' bodies that night, a common practice by U.S. soldiers to document evidence. He said he was outside the house that night and heard two gunshots that appeared to come from inside.

The medic, Spc. John Torres, was acquitted in March of attempted premeditated murder and dereliction of duty for failing to provide aid.

Cpl. Justin Whiteman, accused of placing the pistol by the insurgent's body, was acquitted in March of being an accessory after the fact to attempted premeditated murder and with dereliction of duty.