Conspiracy theorists who question President John F. Kennedy's assassination in 1963 have, over the years, become obsessed with another murder. On Oct. 12, 1964, socialite and artist Mary Pinchot Meyer, a longtime Kennedy mistress, was shot execution-style in broad daylight while walking along the Georgetown canal towpath.

Conspiracy theorists who question President John F. Kennedy's assassination in 1963 have, over the years, become obsessed with another murder. On Oct. 12, 1964, socialite and artist Mary Pinchot Meyer, a longtime Kennedy mistress, was shot execution-style in broad daylight while walking along the Georgetown canal towpath.