Alcatraz Island Engineers began fortifying the island, work which continued until 1858, eventuating in Fortress Alcatraz. The island's first garrison at Camp Alcatraz, numbering about 200 soldiers and 11 cannons, arrived at the end of that year. When the American Civil War broke out in 1861, the island mounted 85 cannons (increased to 105 cannons by 1866) in casemates around its perimeter, though the small size of the garrison meant only a fraction of the guns could be used at one time. At this time it also served as the San Francisco Arsenal for storage of firearms to prevent them falling into
Battle of Alcatraz cellblock. Joe Cretzer was a west coast gangster and member of the Cretzer-Kyle Gang. In 1940 he was sentenced to 25 years for murder. After two escape attempts in the first months of his incarceration, one of which resulted in another murder charge, he was transferred to Alcatraz. In May 1941, Cretzer, Shockley and two other convicts made an escape attempt from one of the prison's workshops. Carnes was the youngest prisoner to reside at Alcatraz, having been convicted of murder in 1943 at the age of 16. He made a number of escape attempts and by 1946, when he