FBI files show decades of threats against Kennedy

The batch of records released yesterday - covering from the mid-1960s through 2001 - was the second since the Federal Bureau of Investigation last year declassified portions of its voluminous file on Kennedy.

The documents show that Kennedy, who represented Massachusetts in the US Senate from 1962 until his death from brain cancer in 2009, lived under constant threat following the murders of two of his brothers, President John F. Kennedy and Senator Robert F. Kennedy.

The threats surfaced in a variety of ways. Some were contained in letters to Kennedy’s office; others were relayed to law enforcement agencies by anonymous callers or concerned citizens. They spiked during his failed bid for the presidency in 1980, but continued for the rest of his life.

The FBI spent thousands of hours trying to track down their veracity. In one case, agents sought to trace a threatening letter by analyzing dozens of models of copy machines.

Two of the more unusual cases came in the late 1960s. In the summer of 1968, just weeks after Robert Kennedy’s death, a man called the FBI’s Miami office to report that he, his roommate, a cashier, and a waitress at the New England Oyster House in Coral Gables overheard a patron identify himself as Sonny Capone, the son of the notorious gangster Al Capone, while making a threatening phone call.

“If Edward Kennedy keeps fooling around, he’s going to get it too,’’ the caller, who was apparently drunk, reportedly said. The FBI confirmed Sonny Capone was living in the area, but there is no record in the documents of a follow-up investigation.

In October 1969, the FBI in New York reported that the secretary of William F. Buckley Jr., a leading conservative author and commentator, received an alarming phone call from a woman with a Spanish accent who demanded to speak with him.

The woman said she was from South America, had “newspaper connections’’ there, and had learned that a plot to kill Kennedy was being hatched in Havana. The woman said the plot was being developed by communists to appear as though the conservative right had done it. The FBI waited in vain for her to call back with more details.