Michael Koryta 
Last Words [EPUB ebook] 

Private investigator Mark Novak is still mourning the death of his wife, and it’s affecting his work. With his future on the line, Mark is sent to check out a case in the Midwest town of Garrison, home to a famous but perilous cave system. A girl has died in the caves, and the man who brought her out is still believed by many to be her killer. He begs Novak to uncover what really happened. But Garrison is the kind of place where cold cases stay cold. Mark tries to delve into the town’s secrets, but in the end, he will have to match his wits against the man who knows the caverns better than anyone. A man who seems to have lost his mind. A man who seems to know Mark Novak all too well.