Police charged a Royal Navy sailor on Sunday with murdering an officer aboard a British nuclear-powered submarine.
Able Seaman Ryan Donovan, 22, is also charged with the attempted murder of three other crew on HMS Astute.
Lt. Cmdr. Ian Molyneux, the sub's weapons engineer, was shot dead Friday while the submarine was docked in the southern English port of Southampton.
Another officer was seriously wounded before the gunman was disarmed by fellow sailors and visiting dignitaries.
As well as the murder charge, Donovan is charged with attempting to kill Lt. Cmdr. Christopher Hodge, Petty Officer Christopher Brown and Chief Petty Officer David McCoy. Officials have not said which of the three is the wounded man.
Officials say the incident was not related to terrorism, but have not disclosed a possible motive for the attack.
Donovan is due to appear in court Monday in Southampton, 75 miles (120 kilometers) south of London.
The 1 billion pound ($1.6 billion) Astute is one of Britain's fleet of 11 nuclear-powered submarines. Its short career has been dogged by problems. Originally due to enter service in 2005, it began active duty in 2010, years behind schedule and millions of dollars over budget.
In October, it hit rocks and ran aground near the Isle of Skye off the west coast of Scotland. It was stuck for several hours until it was towed to safety. The vessel's commander was later removed from his post.