The real-life case
As some may know (and everyone should, if they read the trivia section), this was based on an actual murder case in 1952. The novel was written by the defense attorney under a pen name; it and the movie depict what happened in the original case almost exactly.
Here's a link that tells the story, including a photo of the attorney, John Voelker, the defendant, Lt. Coleman Peterson, and his wife Charlotte. Try not to be too disappointed that they look nothing like Jimmy Stewart, Ben Gazzara and (especially) Lee Remick.
http://michi101.blogspot.com/2013/08/felony-friday-anatomy-of-murder-case.html