What's the Name of That Book??? discussion

I read this back in high school. I thought the title was Revolution but I can’t find it.
Anyways, the kid works at a subway or train station and mans the lost and found section. He sees a beat up thick journal and decides to take it home. He reads through it and it has recordings of this guy mutilating animals and then as he goes through the journal more the guy is expressing desires to move up to killing a person.
The teen is then reading through trying to figure out which woman that comes to the subway station is the potential victim for this potential killer before he can actually carry out his plan.
I remember all of this but I don’t remember the characters names or the author.
I remember the cover was blue and had some weird art but again, I just can’t find this book.
Thank you to whoever can find the name of the author and true name of the book.

Acceleration

Thank you!

No prob, glad to help out!