From The New York Times -- By PAUL VITELLO Published: June 19, 2011 Special Agent James P. Hosty had a few dozen cases in his portfolio in October 1963 when his supervisor in the Dallas office of the F.B.I. handed him another. It was the well-thumbed file on a suspected communist agitator and possible spy named Lee Harvey Oswald. Mr. Hosty tried to find Oswald during two trips into the field in early November, without any luck. The two men met for the first time on Nov. 22, 1963. Oswald was being held at Dallas police headquarters, charged with the assassination of President John F. Kennedy and the killing of a Dallas police officer. Mr. Hosty, taking notes as the police interrogated Oswald, was beginning the half of his life that would remain painfully entangled in the mystery and national trauma of the Kennedy assassination. Mr. Hosty, who died of prostate cancer on June 10 in Kansas City, Mo., at 86, always said he regretted not having found Oswald in those weeks before the assassination. But he insisted it would not have made a difference. Oswald had been on the F.B.I.s radar since returning to the United States in 1962, with his Russian wife, after an unsuccessful effort to settle in the Soviet Union. He had been interviewed by other F.B.I. agents and described in their reports as an avowed communist, a potential spy and a heavy drinker, but never as a potential assassin. When asked by a Congressional committee years later why he did not alert the Secret Service to Oswald before the presidents visit, Mr. Hosty replied: The only thing that we could tell the Secret Service was a direct threat to the president. He made no direct threat to the president. Therefore we could not tell them. In fact, it was Mr. Hostys contacts with Oswald, rather than the lack of them, that came to haunt him. In 1975, testifying before Congress, Mr. Hosty admitted having received a letter from Oswald in the weeks before the assassination and destroying it on the day Oswald was killed by Jack Ruby, Nov. 24. He said the letter included Oswalds sharp protest over Mr. Hostys having questioned Oswalds wife, Marina, when the agent made two visits to their home while Oswald was out. Mr. Hosty testified that he destroyed the letter on orders from his supervisor, J. Gordon Shanklin. (Mr. Shanklin denied giving such an order.) Mr. Hosty also figured in a deception involving Oswalds address book. Mr. Hostys name and phone number appeared in the book, but F.B.I. agents in Washington, taking inventory of the contents of it for the Warren Commission, left his name out. (Commission lawyers later obtained the address book and discovered the omission.) Both incidents made Mr. Hosty a lightning rod for suspicion about the credibility of the F.B.I. in the aftermath of the assassination, raising questions for some about what the agency knew and would not tell. For others, the incidents suggested darker possibilities. Mr. Hostys name is ubiquitous in the conspiracy literature. Oliver Stones 1991 movie JFK has a fictionalized version of him at the center of a conspiracy of government operatives who kill the president and set up Oswald an F.B.I. informant in the film to take the fall. The irony was, my dad was a devout Irish-Catholic Democrat Kennedy supporter, said Thomas Hosty, one of Mr. Hostys nine children, a lawyer, who helped his father write his 1995 memoir, Assignment: Oswald. They conceived the project after JFK, he said, to set the record straight. Being portrayed as part of a plot to kill the president, it was just so hurtful to him. In his memoir, Mr. Hosty acknowledges some mistakes but contends that F.B.I. officials made bigger errors first by trying to eliminate evidence that might make it seem as though the agency had any hint of Oswalds plans, and then by letting commission investigators portray Mr. Hosty as a bumbler when the evidence emerged about his contact with Oswald in the weeks before the assassination. I came to understand that one of our jobs was to protect the bureaus image at all costs, he wrote. Mr. Hosty was among 12 agents reprimanded for various investigative improprieties after the release of the Warren Commissions report. In 1965, he was transferred to the F.B.I.s Kansas City office, where he served until his mandatory retirement at age 55, in 1979. After retiring, he granted interviews to every writer and documentary filmmaker who asked him about Dallas, Thomas Hosty said. Even the ones who had some conspiracy agenda, he added. He figured if these people met him, they would see who he was a straight arrow. James Patrick Hosty was born on Aug. 28, 1924, in Chicago, one of seven children of Charlotte Irene and James Hosty Sr., an executive in a sugar company. He served in World War II and later graduated from the University of Notre Dame. He joined the F.B.I. in 1952. He and his wife, Janet, who died in 1999, had 9 children, 7 of whom survive, along with 22 grandchildren and 9 great-grandchildren. In his testimony before the Warren Commission in 1964, Mr. Hosty said he spent the morning of Nov. 22, 1963, in meetings, none of them related to Oswald. On his lunch hour, he went outside to watch the presidents motorcade go by and then crossed the street to get lunch. While he was eating, a waitress told him what she had just heard on the radio. I immediately stopped my lunch, he said, and got back to the office. He found out two hours later that the Dallas police had arrested a suspect and identified him as Lee Harvey Oswald. What was your reaction? the commission investigator asked. Shock, Mr. Hosty said. This article has been revised to reflect the following correction: Correction: June 22, 2011 An obituary on Monday about James P. Hosty, an F.B.I. agent who investigated Lee Harvey Oswald in 1963, misstated at one point Mr. Hostys testimony before the Warren Commission. He did not tell the commission that he had received a letter from Oswald in the weeks before President John F. Kennedys assassination and later destroyed it; Mr. Hosty did not publicly acknowledge receiving that letter until he testified before Congress in 1975.