Get breaking news alerts and special reports. The news and stories that matter, delivered weekday mornings.

The military has launched an investigation into how a U.S. contractor received fatal head wounds while working with special operations Marines in Irbil, Iraq, according to three U.S. officials familiar with the investigation.

The Lockheed Martin employee died at Landstuhl Regional Medical Center in Germany last week, just days after he was found in his barracks room with severe head trauma, according to two U.S. officials.

Let our news meet your inbox. The news and stories that matters, delivered weekday mornings. This site is protected by recaptcha

Now, the Naval Criminal Investigative Service (NCIS) is looking into what two Marine Raiders and one U.S. Navy Special Amphibious Reconnaissance Corpsman know about his injuries and whether a fight on New Year's Day is where he suffered the fatal blows, according to three U.S. officials familiar with the investigation.

A spokesperson for the Naval Criminal Investigative Service said, "NCIS does not discuss the details of ongoing investigations."

A spokesperson for Lockheed Martin acknowledged the death of the employee and said it is supporting the investigation.

"Lockheed Martin was saddened to learn of the loss of one of our employees, who was fatally injured while supporting Special Operations Forces within the Operation Inherent Resolve area of operations in a non-combat related incident," the spokesperson said. "We are supporting the Naval Criminal Investigation Service as they conduct an investigation into the circumstances of his death. Our thoughts are with his family and friends, and we are committed to supporting them during this difficult time."

The entrance of Landstuhl Regional Medical Center in Landstuhl, Germany on Aug 29, 2011. Michael Probst / AP file

Major Nick Mannweiler, a spokesperson for US Marine Corps Forces, Special Operations Command (MARSOC) said, “We are aware of the non-combat related death of a contractor supporting a forward-deployed MARSOC unit in the Operation Inherent Resolve theater of operations. MARSOC is providing all requested support to investigators as they look into this incident.”

The Marines and Sailor have not been detained during the investigation, and remain on duty in Iraq, according to two U.S. officials.

The U.S military has a Special Operations Task Force based in northern Iraq, made up of mainly MARSOC Marines and U.S. Navy SEALS.