I am John Sullivan by Jonathan L. Parks

This book has really been messing with my head. It is like a mixture of Hannibal Lector, American Psycho, Post Office... and something else. I just can't explain it. The psychology, the violence, the unfiltered brutality is so unique. There are also moments where I was literally laughing out loud and also silently cheering for the main character, John Sullivan. Has anyone else read the book? I find myself wanting to talk to other people about it but there is very little information in the google search.