Cpl. Saul H. Lopezromo testified Saturday at the murder trial of Cpl. Trent D. Thomas.
"We were told to crank up the violence level," the newspaper quoted Lopezromo as saying in testimony for the defense.
When a juror asked for further explanation, Lopezromo said: "We beat people, sir."
Weeks after allegedly being criticized by officers for not being tough enough, seven Marines and a Navy corpsman went out late one night to find and kill a suspected insurgent in the village of Hamandiya near the Abu Ghraib prison. The Marines and corpsman were from 2nd Platoon, Kilo Company, 3rd Battalion, 5th Regiment.
Lopezromo said the man was known to his neighbors as the "prince of jihad," and had been arrested several times and later released by the Iraqi legal system.
Unable to find him, the Marines and corpsman dragged another man from his house, fatally shot him, and then planted an AK-47 assault rifle near the body to make it appear he had been killed in a shootout, according to court testimony.
Four Marines and the corpsman, initially charged with murder in the April 2006 killing, have pleaded guilty to reduced charges and been given jail sentences ranging from 10 months to eight years. Thomas, 25, from St. Louis, pleaded guilty but withdrew his plea and is the first defendant to go to court-martial.
Lopezromo, who was not part of the squad on its late-night mission, said he saw nothing wrong with what Thomas did.
"I don't see it as an execution, sir," he told the judge, according to the newspaper. "I see it as killing the enemy."
He said Marines consider all Iraqi men part of the insurgency.
"Because of the way they live, the clans, they're all in it together," he said.
Lopezromo and two other Marines were charged in August with assaulting an Iraqi two weeks before the killing that led to charges against Thomas and the others. Charges against all three were later dropped.
Thomas' attorneys have said he suffers from post-traumatic stress disorder and traumatic brain injury from his combat duty in Fallujah in 2004. They have argued that Thomas believed he was following a lawful order to get tougher with suspected insurgents.
Prosecution witnesses testified that Thomas shot the 52-year-old man at point-blank range after he had already been shot by other Marines and was lying on the ground.
Lopezromo said a procedure called "dead-checking" was routine. If Marines entered a house where a man was wounded, instead of checking to see whether he needed medical aid, they shot him to make sure he was dead, he testified.
"If somebody is worth shooting once, they're worth shooting twice," he said.
The jury comprises three officers and six enlisted personnel, all of whom have served in Iraq. The trial was set to resume Monday.