The first person to die linked to the case was Karyn Kupcinet. In his book, Forgive My Grief, W. Penn Jones reports that "a few days before the assassination, Karyn Kupcinet, 23, was trying to place a long distance telephone call from the Los Angeles area. According to reports, the long distance operator heard Miss Kupcinet scream into the telephone that President Kennedy was going to be killed." Karyn's body was discovered on 30th November, 1963. Police estimated that she had been dead for two days. The New York Times reported that she had been strangled. Her actor boyfriend, Andrew Prine was the main suspect but he was never charged with the murder and the crime remains unsolved.

Some researchers claimed that there was a link between the death of Kupcinet and the assassination of John F. Kennedy. It was argued that the conspirators were trying to frighten off her father and journalist, Irv Kupcinet from telling what he knew.

Grant Stockdale, a close friend of John F. Kennedy died on 2nd December, 1963 when he fell (or was pushed) from his office on the thirteenth story of the Dupont Building in Miami. Stockdale did not leave a suicide note but his friend, George Smathers, claimed that he had become depressed as a result of the death of the president. However, it later became known that four days after the assassination Stockdale flew to Washington and talked with Robert Kennedy and Edward Kennedy. On his return Stockdale told several of his friends that "the world was closing in." On 1st December, he spoke to his attorney, William Frates who later recalled: "He started talking. It didn't make much sense. He said something about 'those guys' trying to get him. Then about the assassination."

After the assassination of President Kennedy, Gary Underhill told his friend, Charlene Fitsimmons, that he was convinced that he had been killed by members of the CIA. He also said: "Oswald is a patsy. They set him up. It's too much. The bastards have done something outrageous. They've killed the President! I've been listening and hearing things. I couldn't believe they'd get away with it, but they did!"

Gary Underhill told friends that he feared for his life: "I know who they are. That's the problem. They know I know. That's why I'm here. I can't stay in New York." Underhill was found dead on 8th May 1964. He had been shot in the head and it was officially ruled that he had committed suicide. However, in his book, Destiny Betrayed (1992), James DiEugenio claimed that the bullet entered the right-handed Underhill's head behind the left ear.

There has been a significant number of people who have died who did appear to have important information about the case. This includes several journalists investigating the murder. On 24th November, 1963, Bill Hunter of the Long Beach Press Telegram and Jim Koethe of the Dallas Times Herald interviewed George Senator. Also there was the attorney Tom Howard. Earlier that day Senator and Howard had both visited Jack Ruby in jail. That evening Senator arranged for Koethe, Hunter and Howard to search Ruby's apartment.

It is not known what the journalists found but on 23rd April 1964, Hunter was shot dead by Creighton Wiggins, a policeman in the pressroom of a Long Beach police station. Wiggins initially claimed that his gun fired when he dropped it and tried to pick it up. In court this was discovered that this was impossible and it was decided that Hunter had been murdered. Wiggins finally admitted he was playing a game of quick draw with his fellow officer. The other officer, Errol F. Greenleaf, testified he had his back turned when the shooting took place. In January 1965, both were convicted and sentenced to three years probation.

Jim Koethe decided to write a book about the assassination of Kennedy. However, he died on 21st September, 1964. It seems that a man broke into his Dallas apartment and killed him by a karate chop to the throat. Tom Howard died of a heart-attack, aged 48, in March, 1965.

On 21st July, 1964, Dr. Mary Sherman was murdered in New Orleans. She had been stabbed in the heart, arm, leg and stomach. Her laboratory was also set on fire. The crime has never been sold. Later Edward T. Haslam published Mary, Ferrie & the Monkey Virus : The Story of an Underground Medical Laboratory. In the book he argued that Sherman was working with David Ferrie. Haslam believed that this Central Intelligence Agency backed research involved disease intelligence gathering and cancer research using laboratory-made biological weapons. Haslam claimed this biological weapon was to be used against Cuba’s Fidel Castro.

Judyth Baker later began giving interviews aboout involvement in an anti-Castro conspiracy. She claims that in 1963 she was recruited by Dr. Canute Michaelson to work with Dr. Alton Ochsner and Dr. Mary Sherman in a CIA secret project. This involved creating the means to insure Fidel Castro developed cancer.

In 1963 Judyth moved to New Orleans where she worked closely with others involved in this plot. This included Lee Harvey Oswald, David Ferrie, Clay Shaw and Guy Bannister. Later she claimed she began an affair with Oswald. The research into this biological weapon was carried out in the homes of Ferrie and Sherman. Oswald role in this conspiracy was to work as a courier. However, the project was abandoned in September, 1963, and Oswald was ordered to Dallas.

Oswald kept in touch with Baker and in November, 1963, he had been forced to join a plot to kill John F. Kennedy. Oswald believed that the conspiracy was being organized by Mafia leader, Carlos Marcello and a CIA agent, David Atlee Phillips. Oswald told her he would do what he could to ensure that Kennedy was not killed. After the assassination of Kennedy and the arrest of Oswald, Baker received a phone-call from David Ferrie warning her that she would be killed if she told anyone about her knowledge of these events.

On 12th October, 1964, Mary Pinchot Meyer was shot dead as she walked along the Chesapeake and Ohio towpath in Georgetown. Henry Wiggins, a car mechanic, was working on a vehicle on Canal Road, when he heard a woman shout out: "Someone help me, someone help me". He then heard two gunshots. Wiggins ran to the edge of the wall overlooking the towpath. He later told police he saw "a black man in a light jacket, dark slacks, and a dark cap standing over the body of a white woman."

Soon afterwards Raymond Crump, a black man, was found not far from the murder scene. He was arrested and charged with Mary's murder. The towpath and the river were searched but no murder weapon was ever found.

The media did not report at the time that Mary Pinchot Meyer had been having an affair with John F. Kennedy. Nor did it reveal that her former husband, Cord Meyer, was a senior figure in CIA's covert operations. As a result, there was little public interest in the case.

During the trial Wiggins was unable to identify Raymond Crump as the man standing over Meyer's body. The prosecution was also handicapped by the fact that the police had been unable to find the murder weapon at the scene of the crime. On 29th July, 1965, Crump was acquitted of murdering Mary Meyer. The case remains unsolved.

In March, 1976, James Truitt gave an interview to the National Enquirer. Truitt told the newspaper that Mary Pinchot Meyer was having an affair with John F. Kennedy. He also claimed that Meyer had told his wife, Ann Truitt, that she was keeping an account of this relationship in her diary. Meyer asked Truitt to take possession of a private diary "if anything ever happened to me".

Ann Truitt was living in Tokyo at the time of the murder. She phoned Ben Bradlee at his home and asked him if he had found the diary. Bradlee, who claimed he was unaware of his sister-in-law's affair with Kennedy, knew nothing about the diary. He later recalled what he did after Truitt's phone-call: "We didn't start looking until the next morning, when Tony and I walked around the corner a few blocks to Mary's house. It was locked, as we had expected, but when we got inside, we found Jim Angleton, and to our complete surprise he told us he, too, was looking for Mary's diary."

James Angleton, CIA counterintelligence chief, admitted that he knew of Mary's relationship with John F. Kennedy and was searching her home looking for her diary and any letters that would reveal details of the affair. According to Ben Bradlee, it was Mary's sister, Antoinette Bradlee, who found the diary and letters a few days later. It was claimed that the diary was in a metal box in Mary's studio. The contents of the box were given to Angleton who claimed he burnt the diary. Angleton later admitted that Mary recorded in her diary that she had taken LSD with Kennedy before "they made love".

Leo Damore claimed in an article that appeared in the New York Post that the reason Angleton and Bradlee were looking for the diary was that: "She (Meyer) had access to the highest levels. She was involved in illegal drug activity. What do you think it would do to the beatification of Kennedy if this woman said, 'It wasn't Camelot, it was Caligula's court'?" Damore also said that a figure close to the CIA had told him that Mary's death had been a professional "hit".

There is another possible reason why both Angleton and Bradlee were searching for documents in Meyer's house. Were they looking for material that Meyer had been collecting on CIA's covert activities?

In 1963 Desmond FitzGerald was in charge of the CIA's Cuban Task Force. In this post he personally organized three different plots to assassinate Fidel Castro. According to Dick Russell, FitzGerald had a meeting in France with a Cuban code-named AM/LASH, finalising a plan to eliminate Castro, at the same time John F. Kennedy was assassinated. FitzGerald died of a heart attack while playing tennis in Virginia on 23rd July, 1967.

Lisa Howard died at East Hampton, Long Island, on 4th July, 1965. It was officially reported that she had committed suicide. Apparently, she had taken one hundred phenobarbitols. It was claimed she was depressed as a result of losing her job and suffering a miscarriage. At first no one associated Howard's death with the Kennedy assassination. However, it has recently emerged that Howard was involved in secret negotiations with Fidel Castro on behalf of John F. Kennedy.

Winston Scott was the CIA's station chief in Mexico. Scott retired in 1969 and wrote a memoir about his time in the FBI, OSS and the CIA. He completed the manuscript, It Came To Late, and made plans to discuss the contents of the book with CIA director, Richard Helms, in Washington on 30th April, 1971. Four days before the agreed meeting Scott died of a heart attack.

Michael Scott told Dick Russell that James Angleton took away his father's manuscript. Angleton also confiscated three large cartons of files including a tape-recording of the voice of Lee Harvey Oswald. Michael Scott was also told by a CIA source that his father had not died from natural causes. Scott eventually got his father's manuscript back from the CIA. However, 150 pages were missing. Chapters 13 to 16 were deleted in their entirety. In fact, everything about his life after 1947 had been removed on grounds of national security.

Nancy Carole Tyler worked as secretary to Bobby Baker. At the time of the assassination she was living with Mary Jo Kopechne, who worked for George Smathers (she later became secretary to Robert Kennedy). According to W. Penn Jones Jr, it was Tyler and Kopechne who told Baker that John F. Kennedy planned to replace Lyndon B. Johnson as vice president. Tyler died in a plane crash, near Ocean City, Maryland, on 10th May, 1965. Kopechne was later to die in the car of Edward Kennedy on 18th July, 1969.

Dorothy Kilgallen, a crime reporter of the New York Journal, obtained a private interview with Jack Ruby. She told friends that she had information that would "break the case wide open". Aware of what had happened to Bill Hunter and Jim Koethe, she handed her interview notes to her friend Margaret Smith. On 8th November, 1965, Kilgallen, was found dead. It was reported she had committed suicide. Her friend, Margaret Smith, died two days later.

Two of the men that Jim Garrison believed were involved in the conspiracy to kill Kennedy, Guy Bannister (June, 1964), David Ferrie ( February, 1967) and Eladio del Valle (February, 1967) died before they could be brought to court.

Roger D. Craig was on duty in Dallas on 22nd November, 1963. After hearing the firing at President John F. Kennedy he ran towards the Grassy Knoll where he interviewed witnesses to the shooting. About 15 minutes later he saw a man running from the back door of the Texas Book Depository down the slope to Elm Street. He then got into a Nash station wagon.

Craig saw the man again in the office of Captain Will Fitz. It was the recently arrested Lee Harvey Oswald. When Craig told his story about the man being picked up by the station wagon, Oswald replied: "That station wagon belongs to Mrs. Paine... Don't try to tie her into this. She had nothing to do with it."

Craig was also with Seymour Weitzman when the rifle was found on the sixth floor of the Texas Book Depository. He insisted that the rifle was a 7.65 Mauser and not a Mannlicher-Carcano.

Craig became unpopular with senior police officers in Dallas when he testified before the Warren Commission. He insisted he had seen Lee Harvey Oswald get into the station wagon 15 minutes after the shooting. This was ignored by Earl Warren and his team because it showed that at least two people were involved in the assassination. Craig, unlike Seymour Weitzman, refused to change his mind about finding a Mauser rather than a Mannlicher-Carcano in the Texas Book Depository. Craig was fired from the police department in 1967 after he was found to have discussed his evidence with a journalist.

In 1967 Roger D. Craig went to New Orleans and was a prosecution witness at the trial of Clay Shaw. Later that year he was shot at while walking to a car park. The bullet only grazed his head. In 1973 a car forced Craig's car off a mountain road. He was badly injured but he survived the accident. In 1974 he surviving another shooting in Waxahachie, Texas. The following year he was seriously wounded when his car engine exploded. Craig told friends that the Mafia had decided to kill him. Craig was found dead from on 15th May, 1975. It was later decided he had died as a result of self-inflicted gunshot wounds.

When the Select Committee on Intelligence Activities and Select Committee on Assassinations began investigating Kennedy's death in the 1970s the deaths of potential witnesses increased dramatically. This included several criminals with possible links to the assassination of John F. Kennedy. Those who were killed or who died in suspicious circumstances during this period included Malcolm Wallace (1971), Lucien Sarti (1972), Charles Willoughby (1972), Thomas Davis (1973), Richard Cain (1973), Dave Yarras (1974), Sam Giancana (1975), Jimmy Hoffa (1975), Roland Masferrer (1975), Johnny Roselli (1976), George De Mohrenschildt (1977), Charlie Nicoletti (1977) and Carlos Prio (1977).

William Sullivan, the main figure in the FBI involved in the Executive Action project, was shot dead near his home in Sugar Hill, New Hampshire, on 9th November, 1977. Sullivan had been scheduled to testify before the House Select Committee on Assassinations.

Sullivan was one of six top FBI officials who died in a six month period in 1977. Others who were due to appear before the committee who died included Louis Nicholas, special assistant to J. Edgar Hoover and his liaison with the Warren Commission; Alan H. Belmont, special assistant to Hoover; James Cadigan, document expert with access to documents that related to death of John F. Kennedy; J. M. English, former head of FBI Forensic Sciences Laboratory where Oswald's rifle and pistol were tested and Donald Kaylor, FBI fingerprint chemist who examined prints found at the assassination scene.

Several important figures in the Central Intelligence Agency died before they could give evidence to the House Select Committee on Assassinations investigations. Sheffield Edwards, the CIA official who attempted to organize the assassination of Fidel Castro, died in July, 1975. William Harvey, head of the ZR/RIFLE project, died as a result of complications from heart surgery in June, 1976. William Pawley, who took part in Operation Tilt, died of gunshot wounds in January, 1977. David Morales, who some believe organized the assassination, died aged 53, on 8th May, 1978. Another important figure in CIA covert operations, Thomas Karamessines died of a heart attack on 4th September, 1978.

John Paisley was deputy director of the Office of Strategic Research. On 24th September, 1978, John Paisley, took a trip on his motorized sailboat on Chesapeake Bay. Two days later his boat was found moored in Solomons, Maryland. Paisley's body was found in Maryland's Patuxent River. The body was fixed to diving weights. He had been shot in the head. Police investigators described it as "an execution-type murder". However, officially Paisley's death was recorded as a suicide.

According to the journalist, Victor Marchetti, Paisley was a close friend of Yuri Nosenko. Marchetti also claimed that Paisley knew a great deal about the assassination of John F. Kennedy and was murdered during the House Select Committee on Assassinations investigation because he was "about to blow the whistle".