CREEP by Eireann Corrigan

Glennon Heights is a quiet place. When the Donahues buy the house at 16 Olcott Place, things begin to change.

Olivia is excited when she learns that her new neighbors have a kids, and when one of them is a girl her age, it's even better. Janie and Olivia will be starting high school together. The older Donahue children, twins Lucy and Ben, will be seniors. In the weeks before the start of school, Olivia spends much of the time in the home of her new neighbors.

The fun and sun of the last days of summer are interrupted when the Donahues receive several frightening and threatening letters from someone identifying as The Sentry of Glennon Heights. Evidently, the previous owners of the huge, old house had also received letters. Was that why they sold the place and moved?

After several police visits that end without clues of any kind, Mr. Donahue is furious and afraid for his family. He files a lawsuit against the realtor claiming they should have been warned about the creepiness of these threatening letters.

Olivia, along with Janie and Ben, decide to do some investigating of their own. What they find is even more disturbing than they anticipated. 

CREEP by Eireann Corrigan is a fast-paced, thriller. It is perfect for middle grade and older readers looking for a good mystery.