Marita Lorenz, who became pregnant from an affair with Fidel Castro but who balked at poisoning him in an American-linked plot by Cuban counter-revolutionaries, died on Aug. 31 in Oberhausen, Germany. She was 80.

The cause was cardiac failure, her daughter, Monica Mercedes Pérez Jiménez, said.

Ms. Lorenz — the daughter of an American actress with whom she was interned as a child in a concentration camp and a father who commanded a U-boat fleet — led a colorful life so implausible that separating the morsels of reality from what may be illusory, or at any rate unprovable, is all but impossible.

Her romance with Castro and another with the Venezuelan generalissimo Marcos Pérez Jiménez, who fathered her daughter, both appear to have been confirmed . But whether she and Castro produced a son named Andre, who grew up to be a pediatrician in Cuba, is arguable.

So was her detailed account of her actions on the eve of President John F. Kennedy’s assassination in November 1963. In her telling, she, Frank Sturgis (who was later convicted as one of the Watergate burglars) and Lee Harvey Oswald drove that night to Dallas, where they met with Jack Ruby and E. Howard Hunt (who also later became a Watergate burglar and one of President Richard M. Nixon’s so-called plumbers). Oswald killed Kennedy on Nov. 22; two days later, Ruby murdered Oswald .