FBI agents are making a televised $1m appeal for help catching a notorious gangster thought to be hiding in London.
Bulger's picture is beside Osama Bin Laden's on the FBI website
Irish-American gangster James 'Whitey' Bulger ranks alongside Osama Bin Laden as one of America's most wanted men.
On the run since 1995, he was last spotted in a Piccadilly hotel in central London last September.
He is wanted in the US for 19 murders, extortion, racketeering and money laundering.
FBI agents will be offering the reward, equivalent to £636,000, for help catching Bulger on the BBC's Crimewatch programme on Wednesday.
The 73-year-old gained his ruthless reputation as a Boston crime boss in the 1970s and 1980s but became an FBI informer.
He went on the run after being tipped off about an impending raid by an FBI agent who was on his payroll.
Thomas F Baxter
Bulger has a violent temper and is said to carry a knife at all times.
FBI agents have been in London looking for him after a former friend, who did not know Bulger was a criminal, spotted him on 10 September.
He only got in touch with police after recognising Bulger from an FBI 'Most Wanted' poster featured on the Anthony Hopkins film Hannibal.
Bulger is thought to be on the run with his lover Catherine Greig and is considered a master of disguise.
Scotland Yard Detective Superintendent Nigel Mawer said: "James Bulger should not be approached.
"Anyone knowing his whereabouts or who has information on him at all should contact police immediately."