The United States Naval Criminal Investigative Service (NCIS) is the primary investigative law enforcement agency of the United States Department of the Navy. Its primary function is to investigate major criminal activities involving the Navy and Marine Corps. However, its broad mandate includes national security, counterintelligence, counterterrorism, cyberwarfare, and the protection of U.S. naval assets worldwide. NCIS is the successor organization to the former Naval Investigative Service (NIS), which was established by the Office of Naval Intelligence after World War II. One-half of NCIS personnel are civilian, with the other half being US government investigators — 1811 series special agents. NCIS agents are armed federal law enforcement investigators, who frequently coordinate with other U.S. government agencies and have a presence in more than 41 countries and on U.S. Navy vessels. NCIS special agents are supported by analysts and other experts skilled in disciplines such as forensics, surveillance, surveillance countermeasures, computer investigations, physical security, and polygraph examinations.