The Devil's Tombstone, third in the Catskill Mountains Mysteries, a series that began with Hemlock Lake, is now out.
Here's a summary:

The Catskill Mountains are rich in folklore, legends, and tales of the supernatural. Once guided by ghosts, Dan Stone doesnít disbelieve what canít be explained. And thereís no logical reason for the patch of blighted ground beside a boulder near Hemlock Lake. Known as the Devilís Tombstone, the rock marks the spot where, two centuries earlier, a man murdered his young wife and then disappeared.

As a part-time investigator assigned to cold cases, Dan is troubled by more recent deaths and disappearances. Reviewing files dating back two decades, he sets out to discover new leads. But itís slow going. A massive snowstorm socks the mountains. Danís infant son disrupts his sleep. And dynamic preacher Wesley Falton pitches his revival tent, challenging Hemlock Lake traditions and the spiritual leadership of Reverend James Balforth.

As Dan digs deeper into the past, he suspects his cold cases are linked to a fresh murder. When hard evidence eludes him, he appeals for help from beyond the grave. As he does, he wonders whether ghosts make their presence felt because we believe in them, or because they believe in us.

The answer may lie at the Devilís Tombstone.