Who invented ncis?

NCIS, the television series, was not invented by a single person. It was created by Donald P. Bellisario, who served as the executive producer, writer, and director of the show.

However, it's important to note that NCIS is based on the real-life Naval Criminal Investigative Service, which is a federal law enforcement agency that investigates crimes related to the U.S. Navy and Marine Corps. So, while Bellisario is credited with creating the television show, the concept itself is rooted in the actual NCIS organization.