Necropolis PD
(Book)

How do you solve a mystery in the city of the dead? Jacob Green was just an average college student. But three months ago, he ran through the wrong door and found himself trapped in the city of Meridian - a literal necropolis, concealed from the modern world, made up of forgotten places and populated entirely by the dead. As the only living, breathing resident, Jake has struggled to scrape out an existence while waiting for the Necropolis Police Department to decide his fate, and it's not looking good. But when an unusual string of crimes hits the city, Jake's overseer and tormentor, NPD Detective Marsh offers him a deal: Jake's life in exchange for helping them solve the worst series of crimes in the necropolis' history. Someone, or some thing is killing the dead, and if Jake can't figure out who's responsible, he could be next.