There was a movie “Hollywoodland” about the death of George Reeves. One of the characters was Toni Mannix. I wonder if she was the wife of the guy in this story.
It was a pretty good movie but did not claim to be true. Still it had a scenario in which Reeves was murdered and the crime covered up.
That sounds more believable after reading this article.
Eddie Mannix is also a character (played by Josh Brolin) in Hail, Caesar.
It's a made-up story, but some of the subplots may be based on real-life.