Perhaps the most notorious unsolved murder of a woman in America in the 20th century was the slaying in our nation's capital of Mary Pinchot Meyer on Oct. 12, 1964. While taking her daily walk on a towpath in a public park in Washington, D.C. in broad daylight, Meyer was suddenly and violently seized from behind by a powerful attacker who, after a short struggle, shot her twice with a handgun, execution-style, at very close range. The first shot sent a bullet into the left side of her head about two inches in front of the ear. It inflicted a lethal wound which would have soon killed her had it not been for the fatal second shot, fired from above her right shoulder a few seconds later, which sent a bullet through her chest cavity into her aorta and killed her instantly. The shooter was an expert marksman and unusually fired the first shot with one hand and the second shot with the other hand. An ambidextrous murderer so accomplished that the first of the shots was a headshot and both shots were mortal. Despite thorough, extensive searches by large numbers of police officers, the .38 cal. murder weapon was never found.
Wilkes, Donald E. Jr., "The Unsolved Murder of JFK's Mistress" (2012). Popular Media. Paper 148.