Boston - Newly released FBI documents reveal that threats against the late Sen. Edward Kennedy continued long after the assassinations of his brothers, at one point prompting the future owner of the New York Yankees to hire personal security guards for the Massachusetts Democrat.

One of the alleged threats to Kennedy came ahead of a planned visit to Ocala, Fla., in January 1972.

The visit came just four years after Kennedy's brother, the late Sen. Robert Kennedy, was slain in Los Angeles in 1968 and nine years after his brother, the late President John F. Kennedy, was gunned down in Dallas in 1963.

The FBI obtained two letters warning Kennedy against speaking publicly in Ocala. "It will not be safe for you," one of the letters reads. "Some of us are for you, but big majority are against you. It will only stir the mess you were in with Mary Joe."

The reference is apparently to Kennedy's car accident on Chappaquiddick Island off the coast of Massachusetts in July 1969 that killed Mary Jo Kopechne, a young woman who had been a worker in Robert Kennedy's campaign.

According to a subsequent report in the FBI files, Kennedy arrived in Ocala by private plane and stayed at the home of George Steinbrenner, identified in the report as the owner of the Kinsman Stud Farm.

Steinbrenner, who would go on to buy the New York Yankees the following year, hired "eight to ten men from the Pinkerton Detective Agency to guard Kennedy and party," according to a report sent to the FBI by the Marion County Sheriff's Office at the time.

The sheriff's office also assigned two officers to help protect Kennedy.

The report also warns that "two Ocala women have been attempting to polarize action against Kennedy in the form of a demonstration." One of the women had lost a son in the Vietnam War and held the late President Kennedy responsible, the report said.

The more than 1,400 documents made public by the FBI on Monday also include a June 25, 1968, report of a threat called in from a pay phone at a Coral Gables, Fla., restaurant. The call was overheard by a waitress.

The caller, who identified himself as Sonny Capone, allegedly stated that "If Edward Kennedy keeps fooling around, he was going to get it too."

The FBI reported that a Sonny Capone, "son of the late Al (Scarface) Capone, a notorious hoodlum from Chicago" had lived in Florida as recently as 1966, two years before the phone call.

The report didn't confirm whether the individual making the call was, in fact, Al Capone's son.

Other threats against Kennedy included an anonymous November 1965 call to police in Lynn, Mass., warning that "Kennedy will not reach city hall tonight." Kennedy had several local appearances planned, including a stop at Lynn City Hall.