Series numeration from goodreads.com.

On the evening of November 24, 1971, D. B. Cooper hijacked Flight 305--Portland to Seattle--with a fake bomb, collected a ransom of $200,000, and then parachuted from the rear of the plane, disappearing into the night. Fifty years later, Agent Pendergast takes on a bizarre and gruesome case: in the ghost-haunted city of Savannah, Georgia, bodies are found with no blood left in their veins--sowing panic and reviving whispered tales of the infamous Savannah Vampire. As the mystery rises along with the body count, Pendergast and his partner, Agent Coldmoon, race to understand how--or if--these murders are connected to the only unsolved skyjacking in American history.