The researchers were careful about what their finding meant. They explicitly said the best-case results did not prove what happened. They did not calculate a numerical survival probability. They identified a window; they did not claim the men hit that window.
What the 2014 study did was establish that the FBI’s categorical conclusion — that the escape was essentially impossible — overstated what the physical evidence supported. The hydrodynamics of the specific night were not uniformly fatal. Whether Frank Morris and the Anglin brothers knew enough about the tidal cycle, launched at the right moment, and paddled skillfully enough to take advantage of the window the currents provided — these are questions that cannot be resolved by the simulation.
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## The FBI Investigation: Seventeen Years, No Answer
The FBI’s investigation ran from June 12, 1962, to December 31, 1979 — seventeen and a half years.
During that period, investigators interviewed the families of all four men. They reviewed the criminal records of the escapees and their known associates. They followed leads in multiple states. They examined each piece of physical evidence recovered from the bay. They maintained surveillance on family members when leads suggested contact might occur.
The investigation found no evidence of the men alive.
The absence of thefts — specifically, the absence of stolen cars or clothing store burglaries in Marin County or the broader San Francisco Bay Area in the days following the escape — was consistently cited by investigators as one of the stronger indicators that the escape had failed. Allen West had described a plan that required stealing a car and clothing immediately on reaching shore. No such thefts were reported in the target area within what investigators considered the relevant window. This, combined with the physical evidence of flotation devices in the water and the absence of any direct contact from the escapees, led the Bureau to its formal conclusion.