After years of planning, at 1:40 in the afternoon of May 2nd, 1946, six violent convicts (killers and robbers sentenced to a total of 283 years behind bars plus 3 life sentences), leader Bernard Paul Coy (a 45-year-old bank robber from Kentucky), Joseph "Dutch" Cretzer (the former West Coast bank robbing Public Enemy #4 of the FBI's Most Wanted list serving a life sentence for the murder of a U.S. Marshal during an attempted escape while being sentenced in court for other crimes), Sam Shockley (a mentally disturbed bank robber and kidnapper with an IQ of only 54), Miran Thompson (a Texan desperado serving life plus 99 years for robbery, kidnapping and the murder of a Amarillo police officer with a record of eight successful escapes from other prisons and jails), Marvin Hubbard (a robber and kidnapper from Alabama), and Clarence Carnes (a 19-year-old bandit and murderer from Oklahoma know as the "Choctaw Kid") launch an escape attempt that will plunge the federal prison on Alcatraz Island into the bloodiest day in its history.
While confederates distract or take captive cellblock guards, Coy climbs to the top of the three tiered building, and using a short metal tube with a nut and bolt (it has taken over a year to smuggle the pieces necessary to make the device out of the prison's metal shop), spreads the bars of the gun gallery cage (foolishly considered a "safe" convict, Coy has spotted the flaw of unanchored-in-concrete upper bars while spending years going about his daily rounds of sweeping the floor and handing out books and magazines from the prison library), drops down between the bars (sweat, grease, and months of dieting get him skinny enough to accomplish the tight squeeze), and after a furious fist fight with the officer on patrol (Officer Bert Burch who has been distracted by Shockley setting his D-Block isolation cell on fire), acquires the weapons (a pistol, rifle, bullets, and several gas grenades) and keys deemed necessary for the escape.
Where Coy climbed
Everything seemingly in place for the first successful escape from the Rock (all of the eight previous attempts result in failure with six men killed and sixteen captured survivors placed in solitary confinement), Coy's plan (to use the gallery keys to exit the locked cellblock, then with the captured guards as shields, move to the dock where Cretzer has arranged to have a boat waiting) goes awry when the correct exit key can't be found (breaking the standing rules of the prison, Guard Bill Miller has kept the key in his pocket instead of sending it back up to the protected gun gallery after letting a group of convicts into the yard for their post-lunch exercise period). As time slips away (the Cretzer boat leaves when the prisoners don't show up on schedule) in the search for the right key (Miller will hide it in the release basin of the toilet of the cell to which he is confined) and trying to unjam the door to the yard (jammed in an attempt to see if another key will open the door), alternate plans are arrived at (leave on the guard boat, break into the family compound and take guard families captive as bargaining chips off the island, negotiate an escape threatening to kill their captives) that prove equally unsuccessful. Responding to the threat to his prison, Warden James A. Johnston sends men into the gun gallery to re-seize control of the cellblock, but his action only leads to bloodshed as Coy's and Cretzer's accurate rifle and pistol fire drives back the guards (4 are wounded and veteran Officer Harold Stites is killed).
Enraged that the warden has refused to cooperate with their intentions to vacate the premises, and egged on by Shockley (seeking revenge for past wrongs received at the hands of various guards) and Thompson (thinking he won't get the chair if there are no witnesses to his participation in the escape attempt), Cretzer guns down the group's 9 hostages (fired upon at almost point blank range, 2 men are missed entirely and feign death, Officer William Miller is killed, and the rest are seriously wounded but survive due to the efforts of Carnes sneaking back later to apply First Aid) and then his rage not yet assuaged, the crazed Public Enemy goes looking for the man he blames for the failure of the escape ... Bernie Coy (Coy in turn is outraged when he finds Cretzer has killed the unarmed guards, and he begins a cellblock hunt for his former friend).
Power cut, in the darkness that descends on the prison after sunset, a squad of determined guards, covered by officers with sub-machine guns in the gun galleries above, rescue their comrades (and another guard will be wounded by Cretzer firing a pistol from the position he has climbed to atop the cellblock), but unsure of the situation within with Coy, Cretzer, and Hubbard still loose (knowing that escape is not possible, Shockley, Thompson, and Carnes are in their cells when the rescue squad throws the switch that relocks the individual units) and not willing to put any more of his guards at risk, Warden Johnson requests the help of armed troops in restoring order to his prison ... assistance WWII hero General "Vinegar" Joe Stilwell is very glad to provide the next day in the form of two platoons of battle hardened U.S. Marines who treat the prison as if it is a fortified bunker on Iwo Jima, attacking with grenades lowered through holes drilled in the ceiling, concrete pulverizing mortar shells, bazookas rockets, and rounds and rounds of suppressing rifle fire (while thousands of San Franciscans watch the action from Fisherman's Wharf).
Attacking the cellblock
Watching the Battle of Alcatraz
Assaulted for a full day, all three desperate convicts seek the seemingly only safety to be found in the cellblock, the utility corridor between the cell rows ... exactly the place where authorities want them to be. Cornered, the battle is brought to an end by guards unleashing fusillade after fusillade into the narrow passage, a barrage of bullets that finally ends the lives of Coy, Cretzer, and Hubbard sometime on the morning of May 4th.
Left to right ... Hubbard, Coy, and Cretzer
Order restored, the immediate toll of the failed escape attempt is 2 dead guards, 3 dead prisoners, 11 wounded guards, and 1 wounded prisoner.
Guilty ... Carnes, Shockley, and Thompson
Carnage not over though, later, the three convict survivors of the escape plot will also face retribution, going on trial for the deaths of the guards ... guilty as charged, Thompson and Shockley will be sentenced to death and executed in the San Quentin Prison gas chamber on December, 3, 1948, while Carnes is spared death for his efforts to keep the guards alive after their shooting by Cretzer ... spared to serve an additional 99 years on top of the life and 99 years to which he had previously been sentenced (surprisingly, he will eventually be paroled in 1973, unsurprisingly he will violate the conditions of his parole twice and will die in prison of AIDS at the age of 61 in 1988).