Within the Department of the Navy, who is primarily responsible for investigating major criminal offenses?

The Naval Criminal Investigative Service (NCIS) is specifically tasked with investigating major criminal offenses within the Department of the Navy. This includes a wide range of criminal activities, such as fraud, espionage, terrorism, and violent crimes that may occur in a naval context. NCIS operates under the authority of the Secretary of the Navy and is responsible for ensuring the safety and security of naval personnel, assets, and operations.

As the principal investigative agency, NCIS collaborates with other law enforcement and military branches to address complex criminal cases, often involving extensive forensic analysis and investigative techniques. Its personnel are trained in various aspects of law enforcement, making them uniquely qualified to handle cases that are sensitive or that require a specific understanding of military operations.

Other entities mentioned have roles related to law enforcement or national security but do not specifically focus on investigating major criminal offenses within the Navy. The Office of Naval Intelligence primarily focuses on gathering and analyzing intelligence, Naval Security Forces are more involved in force protection and security operations, while the Department of Justice handles legal prosecutions and federal law enforcement on a broader scale. Therefore, NCIS's specific responsibilities and expertise make it the correct answer in this context.