At the age of 21, Keenan was already successful in the business world, as well as being the youngest member of the Los Angeles Stock Exchange. A car accident left Keenan penniless and addicted to painkillers, eventually leading him to hatch the scheme and enlist help in the kidnap-for-ransom plan. Keenan, along with Johnny Irwin and Joe Amsler, conspired to kidnap Frank Sinatra, Jr. Keenan had a psychiatric condition in which he heard voices, and felt that his plan was blessed by God; since he intended to eventually pay the money back, he did not think the kidnapping was immoral. After successfully nabbing Sinatra Jr. from the Harrah's Lodge at South Lake Tahoe, Keenan made contact with Frank Sinatra, Sr. to make ransom arrangements. Sinatra initially offered one million dollars, but Keenan demanded $240,000 instead; significantly less. Despite the nature of the crime, Keenan felt that he was bringing the Sinatra family closer together and assisting the Sinatras in other intangible ways.
Sinatra paid the ransom and the three men released his son. Within days, all three conspirators were apprehended by the FBI. Keenan was sentenced to life plus seventy-five years in prison for his crimes, but only served four and a half years before he was released, because it was determined that he was legally insane at the time of the crime.
After his release, Keenan went on to become successful as a real estate developer. He has been writing a book about the affair, the proceeds of which will go to charity. The event was made into the basis for a Showtime movie released in 2003, Stealing Sinatra, starring David Arquette and William H. Macy.
- Courtroom Television Network, LLC. "The Sinatra Kidnapping Case". Turner Entertainment. Archived from the original on 9 July 2008. Retrieved 2008-07-26.
- Allen, Mike (2006-05-18). "Man who stole Sinatra". The Roanoke Times. Archived from the original on 2013-02-02. Retrieved 2008-07-26.
- Heffernan, Virginia (2004-08-23). "TELEVISION REVIEW; Unkindness Of Strangers (Doobie-Doobie-Doo)". The New York Times Company. Retrieved 2008-07-26.
- This American Life Episode 205: Plan B, "Act Three. Kidnapping as Plan B."
- McLaughlin, Mark (2005-12-08). "Kidnapped: The search for Frank Sinatra Jr". Retrieved 2008-07-27.
- The Mississippi Business Journal (1998). "Deer Island development proposal brings up old Sinatra kidnapping scandal". The Mississippi Business Journal. Retrieved 2008-07-27.
- A&E Television Networks. "Frank Sinatra Jr. endures a frightening ordeal". Archived from the original on 2009-02-27. Retrieved 2008-07-27.
- Glass, Ira (2002-02-01). "This American Life: Plan B". Retrieved 2014-06-05.