Alcatraz Island later invalidated the sale and paid Frémont nothing. Frémont and his heirs sued for compensation during protracted but unsuccessful legal battles that extended into the 1890s. Following the acquisition of California by the United States as a result of the Treaty of Guadalupe Hidalgo (1848) which ended the Mexican–American War, and the onset of the California Gold Rush the following year, the U.S. Army began studying the suitability of Alcatraz Island for the positioning of coastal batteries to protect the approaches to San Francisco Bay. In 1853, under the direction of Zealous B. Tower, the United States Army Corps of
Alcatraz Federal Penitentiary as it was conjectured that they drowned in the bay and their bodies swept out into the sea due to the turbulent bay currents. The most violent escape attempt occurred on May 2–4, 1946, when a failed attempt by six prisoners led to the Battle of Alcatraz, also known as the "Alcatraz Blastout". It was carried out by six prisoners; Bernard Coy, Joseph Cretzer, Sam Shockley, Clarence Carnes, Marvin Hubbard and Miran Thompson. They daringly took control of the cell house by overpowering correctional officers, and were able to enter the weapons room, where they then demanded keys to the