Walter Magnus is a Doctor and a former Medical Examiner with NCIS.
Dr. Magnus was a Medical Examiner with NCIS for many years. He worked on several interesting cases, solving them without access to the technology that the current team has.
NCIS Season 8Edit
Dr. Magnus visits NCIS in the episode "Recruited." He at first just observes the investigation and tours the facility, but later assists Ducky. As the episode goes on, it becomes apparent that something is wrong, and he later disappears, appearing in Abby's lab with no knowledge of what is going on. It is revealed at the end of the episode that he as Alzheimer's, and was visiting the lab to reminisce while he could.