It's been half a century since three inmates pulled off a Houdini-like escape from America's most foreboding maximum security prison, Alcatraz, in San Francisco Bay.
On the night of June 11, 1962, Frank Lee Morris and brothers Clarence and John Anglin climbed through spoon-dug tunnels to escape the 'The Rock', launching themselves into choppy seas on a raft made of rubber raincoats.
The fugitives - all bank robbers - were never found despite one of the biggest-scale manhunts in history. Officials claim they almost certainly drowned in the turbulent tides of the 10-mile-wide bay, with their bodies swept out to sea under the Golden Gate Bridge.
But on the 50 year anniversary of the epic escape, one U.S. marshal is still looking for them, according to The San Francisco Chronicle.
The legendary prison break, plotted by criminal mastermind Morris, is one of the most intriguing unsolved mysteries of our time and was made into the 1979 film 'Escape from Alcatraz' starring Clint Eastwood.
It has been the subject of speculation for generations with some conspiracy theorists believing all three are still alive, now in their 80's, hiding out. Others believe the brothers murdered Morris in the boat or that the mafia assisted their escape.
U.S. marshal Michael Dyke, the only investigator still assigned to the case, believes two of the three made it out alive. But he won't share his reasoning. 'I think there's still a decent chance they made it,' Mr Dyke, who took over the case in 2003, told the Chronicle.
'I can't prove it. Well, nothing I can tell you anyway.'
Mr Dyke has built up four big boxes and 12 gigabytes of 'stuff' in his Alcatraz investigation.
He believes a body wearing prison clothes that was reported by a Norwegian ship floating in the water outside the Golden Gate about a month after the escape was one of the fugitives.
Statistics show two out of three bodies that end up in San Francisco Bay are recovered.
If all three died, that means two bodies should have been found.
Just like any other evening, prison guards regularly checked on the prisoners on the night of the escape and noticed nothing out of the ordinary. But by morning, the three had vanished, leaving pillows and lifelike papier-mache masks with real hair in their beds.
Federal agents, local and state police, coast guard boats and military helicopters scoured the prison complex on Alcatraz Island, then widened the manhunt to the expanse of San Francisco Bay and the surrounding area of Northern California.
The fugitives' raft was found on a nearby island but the three were never found. The prisoners had spent months digging through an eight-inch-thick wall in their cell block using spoons and butter knives. They disguised the holes with painted cardboard.
On the night of the escape, they squeezed through the tunnels into a utility hallway and then climbed down a drainpipe and through an exhaust vent to the roof. They slid down another vent and scaled two barbed wire fences before launching the raft they crafted using 50 raincoats from the northeast edge of the island.
Guards sounded the alarm at 7.15 the next morning. In his Oakland office, Mr Dyke gets a new lead in the case every month or two, he told the Chronicle, but he said the Alcatraz case is more of a professional hobby than a full-time job.
However, there remain active warrants out on all three men. Dead or alive, they will be some of America's most wanted men until they turn 100.
The escape's 50th anniversary is being celebrated with a triathlon on Sunday.
The U.S. Marshals Service is using the milestone to highlight the continued investigation in a bid to warn all those who try to evade the law.
'The ongoing U.S. Marshals investigation of the 1962 escape from Alcatraz federal prison serves as a warning to fugitives that regardless of time, we will continue to look for you and bring you to justice,' U.S. Marshal Don O'Keefe said in a statement.
Mr Dyke told The San Francisco Chronicle that he hopes the fugitives are alive and if he got the chance to meet them, he would shake their hands, before slapping on the handcuffs of course.
'(I would say) you did a good job, and you had a good, long time out. And you're under arrest.'
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