A Royal Navy crewman continues to be questioned on suspicion of murder after a shooting on board a nuclear submarine that left a naval officer dead.
Lt Cdr Ian Molyneux, 36, of Wigan, Greater Manchester, was shot on board HMS Astute as it was docked in Southampton on Friday.
A second officer was also shot and is in hospital.
Police were granted more time by Southampton magistrates to question the arrested man, a Royal Navy serviceman.
Hampshire Police said the full circumstances leading to the events had not yet been established but they were not terrorism-related.
More than 20 witnesses have so far been questioned.
Ch Supt David Thomas, of Hampshire Constabulary, said HMS Astute remained a crime scene and was yet to be released back to the MoD.
Lt Cdr Molyneux's widow, Gillian, described her husband as an "utterly devoted" family man.
Tributes were also paid by First Sea Lord Admiral Sir Mark Stanhope and Capt Phil Buckley, captain of the Faslane Flotilla, to which HMS Astute belongs.
Capt Buckley said Lt Cdr Molyneux's loss would "be felt by his shipmates and across the service. He was, simply, a good bloke".
The injured crewman, who has not been named by the Ministry of Defence (MoD), is conscious and in a stable condition in hospital.
The leader of Southampton City Council, Royston Smith, has described how he dramatically overpowered the firing gunman while on a guided tour of the vessel.
He was on board with the city council's chief executive and mayor as part of a civic party.
Mr Smith, who once served in the RAF, described at least six shots being fired.
He suffered minor cuts and bruising in the struggle.
A group of schoolchildren was about to board the submarine when the shooting began.
HMS Astute has been berthed in Southampton since Wednesday for a five-day official "goodwill" visit.
The 97m (318ft)-long craft is the UK's newest nuclear-powered attack submarine and is based at the Faslane Naval Base on the River Clyde.