"Treasure State" is C.J. Box's newest novel. The protagonist is Cassie Dewell, former LEO now a private investigator. You may remember her from the books about the "Lizard" trucker who kidnapped, imprisoned and killed the women who were hookers working truck stops and she was a LEO who went after him.
She is now a PI in Butte, Montana and is called by a woman in Florida who has been conned out of millions of dollars and wants Cassie to find the guy. The woman had previously hired another PI who was living pretty high on the hog at his clients' expense and tracked the man to Montana before he disappeared. So Cassie is called and takes up the hunt.
The book has its share of mysteries and confrontations. There are many women who have been conned it turns out and there is some law enforcement involved. Crooked, that is.
Old mines play a role, a mysterious poem that provides clues to the location of a hidden treasure plays a role and it's a good book and a fun read.
It's easy to recommend it for some entertaining reading.