The Crystal Cavern by Hannah Alexander

When an ice storm strands Dr. Sable Chamberlin and paramedic Paul Murphy in the southern Missouri hills, they assume they're safe from the mysterious killer responsible for murdering Sable's grandfather and Paul's uncle. But while searching Sable's childhood home and connecting caves for clues, it becomes clear that real danger has followed them. Soon, Sable and Murph, fighting for their lives, discover secrets worth killing for. . .and unexpected treasure more costly than gold. Combining the rich setting of the Ozark hills with compelling and diverse characters, Hannah Alexander has crafted a fast-moving novel sure to keep readers asking the question--whodunit?