The Case of the Wandering Werewolf by Drew Stevenson, 1987.
A boy called Chips approaches Raymond with the story that there might be a werewolf in Lost Woods, outside of town. Chips likes animals, and he has been going into the woods to spring animal traps that someone has been leaving there. One evening, Chips thought he saw a man who seemed to turn into a wolf, and the wolf chased Chips away, only stopping when Chips crossed the creek. Chips has heard of Huntley’s monster hunting activities, and he asks Raymond to tell Huntley about the werewolf and see if he will investigate.
To Raymond’s surprise, Huntley says that he has already heard about the werewolf from another source, which he refuses to reveal. However, he is eager to investigate, on behalf of Chips and his other mysterious source. Verna, who overhears what Chips says about the werewolf, invites herself along on the hunt.
The monster hunt becomes more complicated when Bucky Bovine, a bully at their school, seems determined to stop them from going to Lost Woods to look for the monster. Does Bucky know something about the beast, or could he even be the monster himself?
As always, there are other explanations besides monsters and mysteries that require solving. Fortunately, Huntley is an excellent detective as well as a Monster Hunter, and he puts the pieces together to explain not only the werewolf but other strange things that have been happening around town.