U.S. Naval Criminal Investigative Service agents are investigating allegations that a Marine company killed as many as eight unarmed Iraqi prisoners of war during the battle of Fallujah in November 2004, according to civilian and military sources. The investigation is at least the third into possible war crimes by Marines based here and involves the same company, Kilo Company, 3rd battalion, 1st regiment, that is at the center of the largest allegation of atrocities by U.S. troops in Iraq — the alleged wrongful killing of 24 civilians in Haditha on Nov. 19, 2005. Three enlisted Marines face murder charges in that case, and four officers from the Three-One are accused of failing to investigate the killings.

There is no overlap of the individual Marines accused in the two cases. But some of the Marines under suspicion in the Fallujah case were expected to serve as character witnesses for the Marines accused of murder in the Haditha case.

NCIS officials declined to provide details beyond confirming that they are probing "credible allegations of wrongdoing."

Military journalist and Vietnam veteran Nathaniel Helms, who wrote a book about the Marines in Fallujah and is among those interviewed by NCIS, said investigators are interested in an incident that took place early in the fighting there.

Helms said the Marines captured insurgents during the house-to-house fighting that characterized the battle, called by Marines their most intense urban combat since Vietnam.

After subduing the insurgents and reporting to their superiors, Marines were told to quickly move to another location to help Marines engaged in a firefight.

Helms said Wednesday that when the Marines radioed to their superiors that they were still holding prisoners, the response was, "They're still alive?"

"That was taken to mean, 'Whack those dudes.' So they whacked them and moved on," Helms said. Minutes later an airstrike demolished the house, burying the bodies in rubble.

Helms first posted his account this week on a Web site, www.defendourMarines.com. Senior military sources contacted by the Los Angeles Times confirmed Wednesday that his description matches the incident under investigation.

Helms said he had interviewed Marines about the incident but did not include it in his book about Fallujah, My Men Are My Heroes: The Brad Kasal Story.

Initially unreported, the killings apparently came to light when Ryan Weemer, who was a corporal in Kilo company and is now a civilian, mentioned it during a job interview with the Secret Service when he was asked if he had ever been part of an unjustified killing.

After hearing about the case from the Secret Service, NCIS agents in the spring of 2006 showed up at the Starbucks where Weemer was working to interview him. He did not get the Secret Service job and is now attending college.

In an e-mail, Weemer declined to discuss Fallujah or his interview with NCIS.

"I want it to go away so I can get on with my life," he wrote. "Nothing is going to come of it. The headlines will get it all twisted around anyway."