During World War II, Diehl lied about his age to join the U.S. Army Air Corps at 17, serving as a ball turret gunner on a B-24 Liberator where he flew 24 missions over Germany.
[1] He was the recipient of the Distinguished Flying Cross, the Purple Heart and the Air Medal with three oak leaf clusters.
Diehl relocated to St. Simons Island, Georgia, in the early 1980s, and lived there for the next 15 years before returning to Atlanta.
While living on St. Simons, he completed eight other novels, including Primal Fear, which was adapted into the 1996 film of the same name.
[citation needed] Diehl died of an aortic aneurysm at Emory University Hospital in Atlanta on November 24, 2006.