In August 1960, a CIA official approached Colonel Sheffield Edwards of the Office of Security to determine if he "had assets that may assist in a sensitive mission requiring gangster-type action."
On Monday, Castro accused George Bush, the US president, of "authorising and ordering" an attempt on his life, although his rambling essay on the subject provided no details.
The CIA documents also provided information on wiretapping of US journalists, spying on civil rights and anti-Vietnam war protesters, opening of post between the United States and the Soviet Union and China and break-ins at the homes of former CIA employees and others.
You can see the CIA documents at http://www.foia.cia.gov