NCIS evolved out of the Department of the Navy's (DON's) need for investigative autonomy into a full-fledged federal law enforcement agency with both law enforcement and counterintelligence responsibilities.  NCIS investigative standards and evidence collection methods support prosecution in domestic and international criminal courts. 

NCIS conducts extensive liaison and engagement activities with U.S. and foreign law enforcement organizations.  Partnerships are critical to building capabilities and capacity and collaborating on key maritime security and governance issues.   

• Since 2003, NCIS has conducted more than 1,100 deployments of civilian agents and analysts to Iraq, Afghanistan, the Horn of Africa, and other locations in direct support of combat and counterterrorism operations. Throughout Europe, Africa, Asia, the Americas, and the Middle East, NCIS personnel partner with law enforcement and security agencies to strengthen relationships.
• NCIS agents have played a key role in the investigation and successful prosecution of Somali pirates. 
• NCIS was the first element within the Department of Defense (DoD) to establish a presence at the NATO Cyber Center of Excellence in Estonia. Increased engagement and training activities with foreign counterpart police and coast guard forces have improved the security of U.S. naval forces in foreign ports and other operational venues.
• NCIS provides naval forces with critical regional and local expertise and information through longstanding presence in overseas locations.