The New York Times was the first to report the incident.
The contractor's death followed a physical altercation which took place on New Year's Eve in the city of Erbil, one official said. The Times reported that the contractor was severely wounded and evacuated to Landstuhl, Germany before being pronounced dead on Jan. 4.
In a statement to ABC News, Lockheed Martin confirmed that one of their employees was "fatally injured while supporting Special Operations Forces."
"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 statement 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."
Ed Buice, a spokesperson for the Naval Criminal Investigative Services (NCIS), confirmed the investigation, adding that "NCIS does not discuss the details of ongoing investigations."
A spokesperson for Marine Corps Forces Special Operations Command, Maj. Nicholas Mannweiler, told ABC News that they were aware of the death of the contractor and that “MARSOC is providing all requested support to investigators as they look into this incident.”
There are approximately 5,200 U.S. troops in Iraq.
News of the incident in Erbil comes as elite U.S. forces are under multiple investigations for deadly misconduct.
This spring, a Department of Defense report is due to the Senate and House Armed Services Committee on ethics and standards in the special operations community.