The **Naval Criminal Investigative Service (NCIS)** is the premier federal law enforcement agency serving the U.S. Department of the Navy, tasked primarily with investigating major crimes involving the Navy and Marine Corps. Its mission spans criminal investigations, counterintelligence, counterterrorism, cyberwarfare, and the protection of naval assets worldwide. NCIS agents are armed federal investigators who operate globally, with a presence in over 41 countries and aboard Navy vessels, working closely with other U.S. agencies and international partners[1][2][4]. NCIS originated from the Naval Investigative Service (NIS), established post-World War II under the Office of Naval Intelligence. In 1992, the agency was reorganized and renamed NCIS, marking a significant shift to civilian leadership reporting directly to the Secretary of the Navy, reflecting its evolving role from a military information service to a civilian-led investigative organization[1][3][5]. This restructuring enhanced its independence and professionalism. NCIS handles a broad spectrum of investigations, including serious crimes like homicide, sexual assault, procurement fraud, espionage, and cybercrime. It also enforces the Uniform Code of Military Justice (UCMJ) and U.S. criminal laws when Navy or Marine Corps personnel or assets are involved. Special emphasis is placed on protecting service members and their families through investigations of special victim cases such as sexual abuse and domestic violence. The agency’s Economic Crimes Department safeguards Navy acquisition programs against fraud and corruption, supporting naval readiness[2][4]. Supporting NCIS agents are specialized units such as the Behavioral Science Group, which provides psychological expertise to optimize investigations, and the Office of Military Support, composed of active-duty personnel assisting in protective service and intelligence functions[1]. NCIS’s headquarters is in Quantico, Virginia, and its agents are stationed worldwide, making it a critical element in U.S. national security and military law enforcement[2][4][6]. Known for its discreet professionalism, NCIS plays a vital