The Saboteur by Susan Page Davis

Debra Griffin takes a job at the local police station as secretary to the detective sergeant, Michael Van Sant. Michael is trying to learn who wants to sabotage his unit, and Debra is soon caught up in his hush-hush investigation—while she tries not to fall head over heels for her boss. But danger is nearer than she thinks. When she confronts the saboteur, Mike and his detectives race against the clock. But is one of the men he trusted trying to get Debra out of the way and bring them down?