An Army medic testified at a court-martial Tuesday that after he told his sergeant a wounded insurgent was going to die, the sergeant ordered him to suffocate the Iraqi and then killed the man himself.

Sgt. Leonardo Trevino faces murder and other charges in the death of the man at Muqdadiyah, Iraq, in June 2007.

The medic, Spc. John Torres, said Trevino first asked him what could be done to speed up the Iraqi's death following a gun battle.

Torres said he suggested suffocating the wounded man but said he was only kidding. He said that when Trevino ordered him to carry out the act he only pretended to do so by lightly holding his hand over the man's mouth.

Under cross-examination, he denied defense attorney Richard Stevens' assertion that he felt bad because the Iraqi was dead when he removed his hand from his mouth.

"He wasn't dead," Torres testified. "He was still ... breathing."

Trevino, of San Antonio, has pleaded innocent. If convicted, he faces up to life in a military prison and a discharge. Authorities say he shot the insurgent in the abdomen, a nonfatal wound, then ordered Torres to suffocate him and finally shot the Iraqi in the head and tried to cover up the crime.

In two separate military trials in March, Trevino's two co-defendants were acquitted, including Torres.

Earlier Tuesday, Sgt. Tristan Miller testified that Trevino bragged about killing the Iraqi.

"He said 'The man wouldn't die. I shot him and he wouldn't die. Torres suffocated him and he wouldn't die. Then I shot him in the head,"' Miller testified.

The insurgent was killed after U.S. soldiers engaged in a street gun battle, then followed a blood trail and found the man with about two dozen bullet wounds.

Prosecutors allege Trevino lied by saying the Iraqi was armed, but Stevens said soldiers' stories are inconsistent and contradict photos of the insurgent's body and other evidence. Stevens said the insurgent, whose name U.S. authorities never learned, was still a threat in spite of his wounds.

The trial at Fort Hood, where Trevino is a member of the 1st Cavalry Division, is expected to last a week.