Lying Is A Crime

There is a murderer is the school, no one knows who but some are suspicious of Dream. Every time someone shows love affection to Dream, they die.

Or

Normal high schoolers are doing their every day things when they are called in a lock down for a few hours, no one knows why but they were. Later on they find out there's a murderer but for some reason the school still lets them go to class

(They are all 16 in this book)