Hollow Moon by Rebecca York

Did she save his life only to betray him?

Werewolf detective Knox Marshall makes a near-fatal mistake when he tries to get the goods on a drug lab in isolated Western Maryland. Captured and used as a test subject in a diabolical experiment, he manages to escape. After nurse Maggie Leland finds him naked and wounded in the woods, she patches him up; but she’s hardly prepared for the drug flashbacks that spin his mind out of control or the side effects that turn him on. She and Knox get close quickly. He thinks he’s found his lifemate—until it looks like Maggie is working with the drug dealers. When he realizes he’s wrong, is it, too late to save her life?