Who is responsible for investigating actual, suspected, or alleged national security incidents within the DON?

The responsibility for investigating actual, suspected, or alleged national security incidents within the Department of the Navy (DON) falls to the Naval Criminal Investigative Service (NCIS). NCIS is tasked with safeguarding the Department of the Navy's personnel and resources through thorough investigations and intelligence operations. This role is critical because national security incidents can have significant implications for the safety and effectiveness of military operations.

NCIS has specialized training and authority to handle sensitive investigations pertaining to potential threats against naval operations, ensuring that any incidents are appropriately assessed and managed. Their focus is specifically within the Navy and Marine Corps, allowing them to respond quickly and effectively to incidents that could impact national security.

The other agencies listed have distinct roles that do not specifically pertain to the DON in the same manner. For example, the FBI has a broader jurisdiction that includes a variety of federal law enforcement issues, while the DoD Inspector General's role is primarily oversight and accountability regarding Department of Defense operations. The Defense Security Service also plays a crucial role in security but primarily focuses on personnel security and safeguarding classified information rather than directly investigating incidents. Thus, NCIS is uniquely positioned to carry out the investigative responsibilities for national security incidents within the DON.