Piper is a novel written by Brett Rutherford and John Robertson. It was first published in 1986.
Description[]
The town of Elliot would have liked nothing better than to put up a billboard that reads NOTHING EVER HAPPENS IN OUR TOWN. But after the children's clinic burned to the ground, that was no longer true. Suddenly, for police officer Eddie Hecht, it seemed every night brought a bizarre new crime, another gruesome murder. And the crazy thing was, each case somehow involved a child...
Ten-year-old Timmy Hecht knew something big was happening because his dad was always on duty. And when he came home he was too grouchy and tired to hear about Timmy's new friend, the one who came to his window at night and asked him things. Things about school. Things about the other children. It must be lonely out there in the cold and dark. Maybe next time, Timmy would go out and play with him, and bring all his friends...