Here is some info for the back cover of the book (fit what you can):

For over seven years, the Four Monkey Killer has terrorized the residents of Chicago. When his body is discovered, the police quickly realize he was on his way to deliver one final message, one which proves he has taken another victim, a victim who may still be alive.

As the lead investigator on the 4MK task force, Detective Sam Porter knows even in death, the killer is far from done. When he discovers the killer’s personal diary, he finds himself caught up in the mind of a psychopath, unraveling a twisted history in hopes of finding one last girl, all while struggling with personal demons of his own.

With only a handful of clues, the elusive killer’s identity remains a mystery. The police have little to go on. Time is running out and the Four Monkey Killer taunts from beyond the grave in this fast-paced thriller reminiscent of Se7en and Silence of the Lambs.