Another 1963 memo deals with speculation about a motive in the kidnapping of Frank Sinatra Jr.

CNN: FBI Files: Early Accusations Of J.F.K. Infidelity

According to Ms. Merkelbach, Mr. Harrah, founder of Harrah's Hotel and Casinos, called the home "Villa Harrah" and used it for entertaining celebrities including Frank Sinatra and Sammy Davis Jr.

WSJ: Private Properties: A Bel Air Estate With Winery Lists for $29.5 Million

In the 1950s, this was the go-to destination for Rat Pack party boys like Frank Sinatra and Sammy Davis Jr, who turned the town into their own private playground of jazz, cigars and card games.

BBC: Surf and turf gambling in the Bahamas