Who's Fred Derf?

Chiropractor Fred Derf is found shot on the porch steps of his office. The Pleasant Valley Mayor wants the murderer caught so he contacts former chief of police Sis Steele to lure her back as chief and close this case. Sis's Navy Seal husband who was thought to be dead has returned from ten years imprisonment in Afghanistan with post traumatic stress disorder. Can Sis Steele cope with both the return of her long lost husband with PTSD and a case with no clues? And will she find out exactly who is Fred Derf?