The Black Bullet (Sean O'Brien) by Tom Lowe

Tom Lowe's Sean O'Brien goes Jack Reacher style in this one. It shows how versatile a character O'Brien is, working in more standard PI mysteries as well as more thriller oriented stories as this one. That's because he's got a background as a cop AND a Special Forces guy, so he's got the skills to investigate a murder AND fight terrorists.
During a fishing trip O'Brien discovers a downed submarine and material for a dirty bomb. When it becomes national news he's contacted by the granddaughter of a man who got killed sixty-seven years ago. It turns out the submarine and the murder are connected. O'Brien has to fight Russian mobsters and terrorists for the uranium and uncover the mystery behind the 67 year old murder, dealing with all kinds of agencies.
There's a lot of action in this book. I usually have a hard time with big budget action flicks style action in books because they're hard to read, but Tom pulls it of.
Looking forward to more of O'Brien, in many ways the ultimate series protagonist. He's got everything a hardboiled hero needs.