A Step into the Dark — Vince Vogel

London detective Jack Sheridan is drawn into a killer's twisted game when a prisoner begins receiving letters purportedly describing a series of murders. The prisoner in question just happens to be a man Jack put away nearly thirty years ago. A serial rapist who murdered three elderly women in their homes. With the prisoner and the killer seemingly working together, Jack has to figure out who the man is while also trying to guess what he wants with Jack specifically. Take a step into the dark, the killer suggests. But it is what is inside that darkness that will consume Jack and change him forever.