Plum Spooky by Janet Evanovich

Bounty hunter Stephanie Plum has been looking for Martin Munch all week. He skipped out of town, missing a court date after beating up his boss at a research lab and stealing a magnetometer. Then Stephanie's friend, Diesel, moves himself into her apartment because he's looking for a guy named Wulf who's been seen with Munch. Diesel has a feeling that Wulf and Munch are up to no good and tells Stephanie that Wulf gets pleasure out of doing harm to people. Stephanie also has another new roommate, a monkey named Carl that she's been asked to babysit. When it looks as if Munch and Wulf have decamped to the Pine Barrens (an area of South Jersey populated by few people and widespread forests), Stephanie and friends are forced to head down there. Soon, the gang are in way over their madcap heads....