Media tycoon Robert Maxwell was under investigation for alleged war crimes at the time of his death, it has emerged.
Maxwell's body was found in the Atlantic
Detectives were considering Maxwell's admission that while serving as a British Army captain in World War II he shot dead a German civilian.
Maxwell drowned in mysterious circumstances in 1991. It later emerged he had looted an estimated £400m from the Mirror Group pension fund.
The latest investigation is detailed in documents obtained by the Independent.
A Metropolitan Police file was released to the paper under the Freedom of Information Act.
It shows that detectives at the Metropolitan Police were preparing a case for the Crown Prosecution Service.
The incident is said to have taken place in April 1945, when his platoon was trying to capture a German town.
Maxwell said he shot dead the town's mayor after a tank opened fire on them.
The details of the shooting were first disclosed in 1988, when he confessed to it in a biography of him written by Joe Haines.
Maxwell was a Czech refugee who arrived in the UK in 1940
Police began an investigation into the killing when the War Crimes Act came into effect in 1991, following a complaint from a member of the public.
The inquiry was apparently still under way when Maxwell's body was found at sea.
The police file says the case was closed the following year, because it could be "progressed no further".
At the time of his death he was aware he was under investigation and the latest revelation is likely to fuel speculation that he killed himself.
But the author of a book on Maxwell, Tom Bower, said this was "fanciful" - because Maxwell had never shown any remorse or regret over the shooting.
Scotland Yard said it was not yet in a position to comment.