A Chet Gecko Mystery #2 The Mystery of Mr. Nice by Bruce Hale

My third grader picked out this book from the library and read it to himself.
Chet's principal is actually being nice to him.  Now that is a huge mystery!
Does a recent jailbreak have any connections to the transformed principal and new teachers at Emerson Hicky Elementary?
Private-Eye Chet and his partner Natalie (a mockingbird) are determined to solve the case.
Guided Reading Level: O (end of 3rd grade)
Grade Level Equivalent: 3.9
Borrowed from the library.