Christopher LaSalle said that the Behavioral Science Group Therapist came from the Office of the Director of NCIS, located on Telegraph Road, in the Quantico Marine Corp Base. In 2011, NCIS did relocate to said base, but according to the main series starring Mark Harmon, it is still found at the Washington Naval Yard.
When told Dr. Christo comes from headquarters, Christopher mentions Quantico. In the real world, NCIS headquarters is at Quantico, but on the show it is located at the Washington Navy Yard.