Dixie City Jam (Dave Robicheaux #7) by James Lee Burke

As a child he was frightened by the stories...

It's out there, under the salt of the Gulf of Mexico, off the Louisiana coast--a buried Nazi submarine. Detective Dave Robicheaux of the New Ibera Sheriff's office has known if its existence since childhood, when he was terrified by nightmares of the evil Nazi sailors just offshore.

Then, as a teenager, he stumbled upon the sunken sub while scuba diving--but for years he kept the secret of its watery grave.

... And now he must face the terrible reality.

But decades later, when a powerful Jewish activist wants the sub raised, Robicheaux's knowledge puts him at the center of a terrifying struggle of conflicting desires.