I can't remember the name of this book...help? Possibly James Patterson or Jonathon Kellerman?

There's a serial killer who leaves bite marks on his victims (it's not red dragon btw) and the story is about the detective trying to solve the case. Later in the book there appears to be a copycat with the same M.O. as the first serial killer, but the copycat is missing teeth so the police think it's not the same person. It turns out it is the same person, he just takes out his bridge/dentures/false teeth when he does the copycat killings. The serial killer also has a mom that begs for money in the subway if I remember right. And she hoards newspapers or something. I could be completely screwing up the story but I read it 10 years ago or better so it's a little fuzzy. Please help???