CAMP PENDLETON - A Marine lance corporal accused of killing Iraqi civilians told a buddy to shoot women and children cowering in the back bedroom of a Haditha home, his squad mate testified in a rapt courtroom Tuesday.

"I told him that there's womens and kids in that room," Lance Cpl. Humberto Mendoza said.

"He replied, 'Well, shoot them,' " continued Mendoza, whose native language is not English. "I replied, 'There's just womens and kids. There's no males, no threat, no hostile situation.' "

Mendoza said that when he refused the order, Lance Cpl. Stephen Tatum brushed past him and headed into the room himself.

"Next thing I know, I hear a lot of noise in the house," Mendoza said.

Mendoza's testimony came during the second day of an investigative hearing to determine whether there is enough evidence to send Tatum to trial for the killings of six Iraqis and the assaults of two others.

Tatum's attorneys flatly dispute the claims from Mendoza, who has acknowledged on the stand that he initially lied to investigators about the incident and did not report the conversation with Tatum for more than a year.

The defendant's lawyers also point to a polygraph test their client passed. Mendoza - who admitted to killing two unarmed men during the melee - was granted immunity from prosecution for his testimony.

Prosecutors say Tatum and other Marines stormed homes and killed 24 civilians Nov. 19, 2005, in retaliation for a bombing that shredded a Humvee in their convoy. The bombing killed Lance Cpl. Miguel "TJ" Terrazas and wounded two others.

Attorneys for Tatum and his co-defendants say the Marines were the target of gunfire after the explosion, and ran into the homes to chase their attackers.

On the stand, Mendoza said he did not feel threatened by people in the homes, but was told by squad mates that insurgents were inside.

The Haditha incident is the largest civilian killing case to result in criminal charges since the U.S. invasion of Iraq in 2003. Five young Iraqi men were shot to death outside a car that pulled up about the time of the explosion; 19 others were killed in nearby homes.

Questioned by lead prosecutor Lt. Col. Paul Atterbury, Mendoza said that shortly after a squad mate tossed a grenade into a bathroom, he opened a bedroom door and found women and children cowering.

They were alive, he said, and scared. And they were looking at him.

Mendoza said he closed the door and told Tatum what he had seen. That's when Tatum ordered him to shoot them.

"Was he joking?" Atterbury asked.

"No sir, he was very serious," Mendoza replied.

Mendoza returned to the home hours later as part of a team assigned to collect bodies.

"I found all of the womens and childrens dead," Mendoza testified. "They got multiple wounds everywhere."

Mendoza, who was a private first class at the time of the Haditha killings, said he did not know whether the sound he heard in the back bedroom was gunfire or a grenade.

Atterbury asked Mendoza whether he had asked Tatum what happened.

"I just didn't want to ask him," Mendoza replied.

"Why didn't you want to ask?" Atterbury said.

"I dunno, sir, I just …" Mendoza said, not finishing his thought, but sitting silently and looking away.

On Dec. 21, the Marine Corps charged Tatum and three other enlisted men - Lance Cpl. Justin Sharratt, Sgt. Sanick Dela Cruz and Staff Sgt. Frank Wuterich - with the killings. Marine prosecutors also charged four commanding officers with dereliction of duty for allegedly failing to properly investigate and report what happened.

All of the men have said directly or through their attorneys or family members that they are innocent of any wrongdoing.

Tatum easily passed a polygraph test administered to him earlier this year at the request of his attorneys, according to results submitted as evidence.

The polygraph examiner deemed that Tatum had answered truthfully when he said he did not know there were women and children in the room before he opened fire.

During cross-examination, Mendoza acknowledged that he had failed a polygraph test he took after he changed his version of the events.

Tatum's attorney, Jack Zimmerman, suggested during questioning that a 13-year-old girl who survived the attack in the back bedroom said the first Marine to open fire in the room was shorter than she was. Zimmerman noted Mendoza's height, which is 5 feet 4 inches, and Tatum's height, at about 6 feet 2 inches.

Another of Tatum's squad mates testified that he saw Tatum's signature underneath 24 markings he said he believed signified the number of Iraqi victims. The markings were on an item that had belonged to the slain Terrazas, and was to be sent home to Terrazas' family, Dela Cruz said.

Dela Cruz himself faced homicide charges in the Haditha case, but they were dropped in exchange for immunity from prosecution because he agreed to testify against his squad mates.

Tatum's hearing is scheduled to continue through the rest of the week.

- Contact staff writer Teri Figueroa at (760) 631-6624 or tfigueroa@nctimes.com.