As far as mysteries are concerned this wasn't the best that I've read. Provided that Mr. Martin did use the kind of information that any seasoned police officer would know, it still felt like he was throwing out some facts about guns as a way to fill pages. When the true killer was finally revealed, and the real identity of one of the key characters, it didn't give me that "huh" moment.
While I would never deny any author from following through with his/her passion to write, Mr. Martin could probably do better. All in all, this book fell flat for me.