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
Legends of Alcatraz Karpis is said to haunt the prison bakery and kitchen. One visitor and his wife have claimed to have heard canaries singing in what was the cell of Robert Stroud, the "Birdman of Alcatraz", and to have seen him on the bed reading a book, yet Stroud was never permitted to keep birds in his cell as he'd done at former prisons. Numerous investigators and psychics such as Annette Martin and Jeanne Borgen and paranormal teams have sought to "contact spirits" at Alcatraz. KGO Radio Morning News anchor Ted Wygant, a skeptic of the paranormal, visited Alcatraz in 1982 with