WASHINGTON — Navy officials on Tuesday were investigating a shooting on a guided-missile destroyer docked in Norfolk, Va., that left a sailor dead along with a civilian believed to be the gunman.

The shooting occurred about 11:20 p.m. on Monday at Naval Station Norfolk, the world’s largest naval base, prompting a lockdown that lasted about 45 minutes.

Naval security struggled with the suspect, a civilian, on an upper deck of the Mahan, a guided-missile destroyer, according to a statement posted on the base’s Facebook page. The suspect, who did not have a weapon, was able to disarm an officer and shoot a sailor who was responding to the confrontation. Security personnel then killed the suspect.

A Navy spokeswoman, Beth Baker, said earlier reports that the suspect was a contractor were “not necessarily accurate,” saying his identity was still under investigation. The sailor and the suspect were pronounced dead at the scene. There were no other injuries.