Found this on Quora: I don't recall the 'Rose' story below and some other rare - well to me - mentions of sideline characters
Those who believe the WCR believe that Oswald was a lone nut who fate put in the perfect place to kill JFK and that when he saw the parade route in the paper decided he would make himself famous. If that were true no one but Oswald would have been aware JFK would be in danger that day, (With the possible exception of anyone he told about his plans)
First you have Joseph Milteer. An FBI informant taped a conversation with Milteer who said in that tape that JFK was going to be assassinated, shot from a tall building with a patsy arrested quickly and blamed for the shooting. There is a photo that looks remarkably like Milteer in Dealy Plaza. Some claim it isn’t him but his features are unique enough I don’t rule out it being Milteer.
Next you have Rose Cherami. Rose Cheramie was found unconsciousness by the side of the road at Eunice, Louisiana, on 20th November, 1963. Lieutenant Francis Frugé of the Louisiana State Police took her to the state hospital. On the journey Cheramie said that she had been thrown out of a car by two gangsters who worked for Jack Ruby. She claimed that the men were involved in a plot to kill John F. Kennedy. Cheramie added that Kennedy would be killed in Dallas within a few days. Later she told the same story to doctors and nurses who treated her. As she appeared to be under the influence of drugs her story was ignored. Only after JFK was assassinated did they take her story seriously.
Another interesting story is Eugene Dirkin. He was an Army cryptographer assigned to monitor transmissions. and had the army’s highest crypto clearance. He intercepted communications between Bill Harvey and/or Guy Bannister and members of the the French Guerini Mob including people like Lucien Sarti, and Jean Soutre arranging the assassination of JFK for Dallas and in November. He tried to alert top officials and even wrote a letter to Bobby Kennedy warning him of the danger to JFK in Dallas. Dirkin’s life was ruined by his attempts to save JFK.
Richard Nagell is another interesting story. He went into a bank and shot his gun up into the ceiling. He claimed he didn’t want to rob the bank, that he wanted to be arrested so he would be in Jail when JFK was assassinated since some behind the assassination wanted to use him as a Patsy and he wanted to protect himself by having a rock solid alibi.
There are more such as Madeleine Duncan Brown who accompanied LBJ to a party on 11/21/63 and was told by LBJ "After tomorrow, those goddamn Kennedys will never embarrass me again. That's no threat. That's a promise."
Brown said that on New Year's Eve 1963, she met with Lyndon Johnson at the Driskill Hotel in Austin, Texas, and that Johnson confirmed the conspiracy to kill Kennedy, insisting that "Texas oil and ... renegade intelligence bastards in Washington" had been responsible. Brown alleged that Johnson did not attempt to stop the assassination because he hated Kennedy and had an intense desire to be President. Brown also said that she witnessed Oswald meeting with Ruby in the Carousel Club prior to the assassination, but did not specify how long before the assassination this meeting had occurred.
Brown as she looked when she had the affair with Lyndon above. Below a more recent look
There are others who seemed to have know in advance. Even Jack Ruby invited a friend to view the motorcade from a vantage point across from the TSBD and his words were “Come watch the fireworks”
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