SAN DIEGO — A Marine charged with murdering two Iraqi girls and killing other civilians in the town of Haditha believed he was following procedure by confronting a threat with deadly force, his attorney said yesterday at the military equivalent of a grand jury hearing.

Lance Corporal Stephen Tatum has acknowledged killing several Iraqis on November 19, 2005, but he says he was responding to a legitimate threat. His squad killed 24 civilians in Haditha that day after a roadside bomb killed a Marine nearby.

“He was taught that deadly force is the proper response to a threat,” attorney Jack Zimmerman said of Corporal Tatum.

Corporal Tatum also is charged with the negligent homicide of two men, a woman and a child, and with assaulting two men. The Marine, wearing his desert camouflage uniform in military court, spoke only to confirm his identity. If convicted of murder, he faces life in prison.

After the Article 32 investigation, hearing officer Lieutenant Colonel Paul Ware will assess the evidence against Corporal Tatum and make a recommendation about whether he should face a court-martial. The final decision rests with Lieutenant General James Mattis, the general overseeing the deadliest criminal case to emerge from the war.

“Knowing what I know now, I feel badly about killing Iraqi civilians who may have been innocent,” Corporal Tatum told Navy investigators in March 2006. “But I stand fast in my decisions that day, as I reacted to the threats that I perceived at that time.”

The Edmond, Okla., native is the second of three enlisted Marines in the case to face a hearing to assess whether his charges should be referred to a court-martial.

Last week, an investigating officer determined the government’s evidence against Lance Corporal Justin Sharratt was insufficient for a court-martial and recommended that General Mattis drop the charges. Corporal Tatum’s Marine squad went house to house in Haditha looking for insurgents after the roadside bomb exploded.

According to investigative documents, Corporal Tatum and several other Marines went into one house, where he said he and Corporal Hector Salinas threw grenades into a room after hearing what they thought was the metal-on-metal sound of an AK–47 being readied to fire. The squad leader, Staff Sergeant Frank Wuterich and Lance Corporal Humberto Manuel Mendoza then fired into the room.

Corporal Tatum said he joined in the firing and shot at least four people at a distance of about 20 feet. He said he did not positively identify those he shot as insurgents because he considered the entire house to be hostile.

Corporal Mendoza has been given immunity from prosecution and may testify at Corporal Tatum’s hearing.

The preliminary hearing for Sergeant Wuterich, who is charged with murdering 18 Iraqis, is set for August 22.

In another house, Corporal Tatum said he might have shot up to five people. He determined the house was hostile because Sergeant Wuterich began firing.

“Idid notpositivelyidentifyanyone in the room as I could only make out shapes kneeling down, and I considered anyone to be hostile” based on Sergeant Wuterich’s “engagements in the room,” Corporal Tatum told investigators.

Aside from the three enlisted Marines charged with murder, four officers are charged with dereliction of duty for failing to investigate the deaths. A hearing officer for Lieutenant Colonel Jeffrey Chessani, the highest-ranking Marine charged, has recommended he face a court-martial on charges of dereliction of duty and violating a lawful order for failing to investigate the deaths.