Left for Dead by J. A. Jance

Life in southern Arizona is difficult. When deputy sheriff Jose Reyes is shot and left for dead while on the job, someone else is dumping the presumed dead body of a young prostitute close to the Mexican border. A curious chain of events draw these two events closer and closer, and only the stubbornness of a couple of police officers with the assistance of a former police academy classmate, Ali Reynolds, brings this mystery to its logical conclusion. An interesting plot.