What are the motifs in Mind Prey by John Sandford?

Obsession is a recurring idea. John Mail is a young man who was brutally abused by his parents. Mail was often locked in a closet and beaten. Mail develops a cruel streak as a result of his childhood abuse, finding pleasure in watching people's home's burn. Mail also develops an obsession with sex. When Mail is arrested for the arsons, Andi Manette, a graduate student who is seeking her doctorate in psychiatric medicine, begins visiting him in the prison. Mail develops an interest in Andi sexually, imagining what it would be like to have a sexual relationship with her.