All further investigations into the deaths of two US sailors who went overboard from a submarine will be handled by the American authorities.
The nuclear-powered submarine is based at Norfolk, Virginia
The Crown Prosecution Service (CPS) made the announcement after a review of evidence following the deaths of the servicemen in Plymouth Sound.
The men were two of four who fell from the USS Minneapolis-St Paul as it left Devonport Naval Base on 29 December.
They were working in poor weather on the outside casing of the submarine.
After the four sailors went into the sea, a rescue helicopter from RNAS Culdrose picked up the crewmen and took them to Derriford Hospital where two were pronounced dead.
The two other crew - who have not named by the US Navy - suffered minor injuries.
In a statement on Thursday the CPS said: "CPS Devon and Cornwall has now reviewed the initial inquiry evidence and considered the jurisdictional issues following the tragic death of two US Navy submariners on 29th December in Devonport Harbour.
"Roger Coe-Salazar, chief crown prosecutor, has discussed the case with the US authorities and it has been decided, within the framework of the Visiting Forces Act, that the case will be handed to the US authorities for the conduct of all further investigations."
The Virginia-based submarine had stopped in Devonport to allow the crew "some rest and recuperation" and has since continued on its journey.