The Assassination of President Kennedy.
One of the most famous unsolved murder mysteries of the world is the assassination of former US president John F Kennedy. He was shot dead in a presidential motorcade in Dallas, Texas. There are so many theories as to who killed Kennedy. There was a commission appointed called the Warren Commission in 1963-1964 which concluded that a certain Lee Harvey Oswald killed Kennedy and he was acting alone. However, in 1979, The United States house select committee on the assassination gave a report that the Kennedy assassination was a result of conspiracy and it found so many flaws in the original FBI investigation as well as the Warren Commission report. Till today who killed Kennedy and why is yet to be deciphered. www.jfklibrary.org

Jacqueline Kennedy-Onassis believed Vice President Lyndon B. Johnson was behind the assassination of her husband, according to tapes recorded by the former first lady just months after President John F. Kennedy's death, the Daily Mail reported.

The tapes, which are set to be released by ABC News, reportedly reveal that Kennedy-Onassis believed the then-vice president Johnson, along with businessmen in the South, planned the Nov. 22, 1963, assassination of her husband in Dallas, Texas.

"The tabloid reports about the content of the tapes are totally erroneous," an ABC News spokesperson said in a statement to FoxNews.com. "ABC News isn't releasing any content from those tapes until mid-September at which point it will be clear how off base these reports are. The actual content of the tapes provide unique and important insight into our recent past from one of the most fascinating and influential First Ladies in American history."

Kennedy-Onassis thought gunman Lee Harvey Oswald -- long believed to be a lone assassin -- was part of a larger conspiracy involving Johnson, according to the Daily Mail.