A civilian approaching the USS Mahan, a US Navy destroyer at the world’s largest naval base, took a weapon from a sailor who was standing watch and used it to shoot and kill another sailor who was trying to help his embattled colleague, Navy officials said recently.

Navy security forces then killed the suspect, who was authorised to be on Naval Station Norfolk in Virginia and did not bring his own weapon on base, according to Captain Robert Clark, the base’s Commanding Officer. The identities of the civilian and the sailor who were killed have not been released.

No other injuries were reported from the encounter on the USS Mahan, a guided-missile destroyer. It wasn’t immediately clear why the civilian approached the ship or if he ever had access to it previously.

The shooting comes months after a September incident at the Washington Navy Yard, in which a gunman — identified as a contractor and former Navy reservist — killed 12 civilian workers before being shot to death.