ON JUNE 11, 1962, one of the most infamous and elaborate prison breaks in American history took place when three convicts escaped from Alcatraz.

While many believed brothers John and Clarence Anglin and fellow inmate Frank Morris died during the iconic escape, the FBI recently reopened the cold case after receiving a letter claiming to be from one of the trio.

So is it possible three Alcatraz inmates crawled through tunnels they had carved with spoons and escaped into the frigid waters of the San Francisco Bay on a raft made of raincoats?

In short: Yes.

A 2014 study into the escape reported it would have been possible for the three men to survive, but only if they left Alcatraz Island between 11pm and midnight.

Using a computer model with virtual boats and information of the currents on the night of the escape and the following morning, researchers examined what would happen.

Researcher Dr Rolf Hut said the experiment gave the escapees a small chance of success.

“If they hit it exactly at midnight, the beautiful thing is that we see that they would have been sucked out towards the Golden Gate Bridge,” he told BBC at the time.

“But the moment they were close to the Golden Gate would have been the moment the tide reverses.”

Hydraulic engineer at Deltares and expert on particle tracking Dr Fedor Baart said this would have allowed them to reach Horseshoe Bay and land in the Marin Headlands on the north side of the bridge, which fits with evidence in the case.

“The model predicts that any debris would then float back into the bay in the direction of Angel Island, exactly where the FBI found a paddle and some personal belongings,” he said.

Dr Hut added it was interesting to see TV show MythBusters also “found that the most likely landing place was Horseshoe Bay”.

The study believes if the escapees left any earlier than 11pm, they would have almost certainly been pulled out into the ocean.

Likewise, leaving after 1.00am would have resulted in the trio being pulled back into San Francisco Bay toward Oakland and Berkeley.

However, the later greatly diminishes the likelihood of a successful escape for the trio as they would have either died of hypothermia or been spotted when dawn broke because of the time spent in the water.

IS THERE ANYTHING ELSE TO SUGGEST THEY SURVIVED?

The biggest evidence to support the theory of survival is the bodies of the three men have never been found, despite a 10-day search operation over the area and a 17-year investigation.

Another piece of evidence suggesting the escapees survived was a photo showing John and Clarence Anglin living in Brazil in 1975 — some 13 years after the prison break.

The Anglin brothers’ nephews Ken and David Widner handed the image to the FBI and the History Channel, with the pair claiming the photo was taken by the Anglians’ family friend Fred Brizzi.

It is believed Mr Brizzi had bumped into the Anglin brothers in Rio de Janeiro in the ’70s, which is when the picture was captured before being given to the extended family in 1992.

Speaking on the History Channel special Alcatraz: Search for the Truth, retired US marshal who worked on the case for 20 years, Art Roderick, said the photo had been analysed by a forensic artist who concluded it was likely the men in the photo were John and Clarence Anglin.

“This is absolutely the best actionable lead we’ve had,” he said in the special.

US Marshal Michael Dyke has spent most of his life looking into the case, which he said is unable to be closed because no one can prove they’re dead.

Mr Dyke believes Frank Morris was the brains behind the operation who figured out how to give the homemade raft and life vests an airtight seal.

He said it’s likely the trio used a substance similar to shoe repair glue to form the green life vests and raft made out of prison-issue raincoats, with heat from steam pipes used to seal the seams.

“You can see there’s glue around here, and there’s like a wooden mouthpiece,” he told NPRwhile looking at a picture of a vest.

Mr Dyke said even if the boat failed, the men could have survived the cold bay water for at least 2 ½ hours — a finding he made after getting the Coast Guard to run a simulation.

However, comments made to the press by the assistant director of the Bureau of Prisons at the time of the escape suggested otherwise.

“The tides and winds that night were strong. Only a trained athlete could make such a swim,” he said.

Then-14-year-old Devon Mecham who finished a 2009 race called the Alcatraz Challenge — a swim from Alcatraz to San Francisco — said this statement was not entirely true.

“Anyone can do this,” he said. “It’s just scary to get in. A guy in a wheelchair did it.”

Devon’s father, James Mecham, who also finished the race, shared his son’s sentiments.

“I think it’s highly likely that people could swim that,” he said. “That was just for fun. If I was swimming for [my] life? If this was my life on the line? Doesn’t seem like it would be that tough.”

Mr Dyke added that if the men did reach shore, they would have had an eight to 10-hour head start on authorities.

“If they were able to steal a car, even though there was a nationwide manhunt, there’s all kinds of roads they could be on where they would never have been seen,” he said.

“The other possibility is they could have went out of the country, too.”

Do you think the men would have escaped? Continue the conversation in the comments below or with Matthew Dunn on Facebook and Twitter | matthew.dunn2@news.com.au