Read or Suffer -Z

The four of you decided to follow the message. You left school with the roses and drove to the graveyard where Peter's mom lies, which is the graveyard where you think Z will be. This is really hard for Peter because he recently lost his mom in a car accident a few years prior,
"Peter, its going to be alright." Stacy comforted Peter.
"I miss her so much." Cried Peter.
"We all do." You said, sincerely.
You pulled up and got out of the car. expecting to see Z...but there is no one around the gloomy graveyard.
Josh speaks up, "Let's go to Peter's mom grave and put the flowers down... maybe there will be something for us."
"alright then." you groaned.
At the grave, there was an engraving that read:
" I see your grave is filled. I know a lot about you four but you don't know me. One thing is.. My favorite thing to do is read and curl up with a good book in the murder mystery section. Come find me in my spot or you'll be the next murder mystery to solve. -Z"
"Looks like we are going to the library!" Chuckled Peter.
"Wait. do we want to make a game plan in case Z IS at the library?" Suggested Stacy.
"I don't know because I really don't want to be the next victim in his murder mystery." Josh emphasized.
What do YOU think is best?