After months of prowling Internet chat rooms, posing as the mother of two young daughters, Detective Michele Deery thought she had a live one: “parafling,” a married, middle-aged man who claimed he wanted to have sex with her kids. But was he just playing a twisted game of seduction? Both the policewoman and her target give the author their versions of the truth, in a case that challenges the conventional wisdom about online sexual predators, and blurs the lines among crime, “intent,” and enticement.