Results: The June 11 1962 Alcatraz escape was a prison break from Alcatraz Federal Penitentiary, a maximum-security facility located on an island in San Francisco Bay, undertaken by inmates Frank Morris and brothers John and Clarence Anglin.

Morris' accomplices, John and Clarence Anglin, serving time at Alcatraz for bank robbery, were also veterans of the prison system. Convicted along with a third brother, Alfred, they had been incarcerated at a federal penitentiary in Atlanta when they first met Morris. After their own series of escape attempts, John and Clarence were both sent to Alcatraz by mid-1961. Morris and the Anglins had spent three months digging through the air vents in their cells with sharpened spoons purloined from the prison cafeteria. In addition, they fashioned lifelike dummy heads out of paper, soap and human hair from the prison barbershop, they left the papier-maché dummies in their beds. Have you seen any of the films about Alcatraz?

A fourth man, Allen West, who also participated in the escape plot, was serving his second term at the Rock. Left behind on the night of the escape, West later told the authorities much of what is now known about the complicated scheme, and even claimed to have been the mastermind himself. According to West–who finally managed to escape his cell and make it to the rooftop, only to find that his fellow inmates had disappeared–the plan had been to use the makeshift raft to reach Angel Island. After some rest, the men would then reenter the bay on the opposite site of the island and swim through the so-called Raccoon Straits on their way to Marin County, where they would steal a car and burglarize a clothing store before going their separate ways. A Norwegian freighter reported seeing a body floating 20 miles northwest of Golden Gate Bridge on July 17, wearing what appeared to be denim trousers similar to those issued by the prison. Do you think they made a successful escape?

Though the FBI still maintains active arrest warrants for all three men, they are officially listed as missing and presumed drowned, victims of the frigid waters and swift currents of San Francisco Bay. But the inmates' bodies were never found, and some people continue to believe that Morris and the Anglins may have survived. On March 21, 1963, less than a year after the escape attempt, the federal prison on Alcatraz Island closed. It had been the most expensive of all U.S. state or federal prisons to operate, primarily due to the cost of transporting fresh water to the island and evacuating waste. Now operated by the National Park Service, "The Rock" is now one of San Francisco's most popular tourist attractions. Have you ever visited Alcatraz?

The FBI closed its case in 1979, concluding that the escapees were unlikely to have survived a treacherous swim of more than a mile of frigid waters to the mainland. A letter allegedly written by one of the escapees recently came to light The FBI says this is the most recent piece of evidence that forced the agency to reopen the iconic cold case. The letter was sent to the San Francisco Police Department's Richmond station in 2013. The U.S. Marshals, which is the sole agency investigating the case today, says the FBI lab examined the letter for fingerprints and DNA, and the handwriting. The FBI's results were inconclusive. This leaves the case in limbo. Does it surprise you that they claim not to have found any conclusive evidence to solve this mystery?

The letter was sent to the San Francisco Police Department's Richmond station in 2013. "My name is John Anglin. I escape from Alcatraz in June 1962 with my brother Clarence and Frank Morris. I'm 83 years old and in bad shape. I have cancer. Yes we all made it that night but barely!" According to the letter, Frank died in 2008 and John's brother died three years later. The writer makes a deal -- "If you announce on TV that I will be promised to first go to jail for no more than a year and get medical attention, I will write back to let you know exactly where I am. This is no joke ..." The writer of the letter says he spent many years after his escape from Alcatraz living in Seattle. He also mentions that he lived in North Dakota for 8 years, and currently lives in Southern California. "The Federal Bureau of Prisons say that they drowned once they got off of Alcatraz and their bodies were swept out to the Pacific Ocean -- end of story," said National Park Service Ranger John Cantwell. Who do you believe?

Many books have been written about Alcatraz. Have you read any of the following books?