In the spring of 1989, a troubled teen-ager in Arizona became obsessed with the televised image of a young actress. Though they had never met, he yearned to be close to her, to possess her somehow. So he did a very American thing: he turned to the free market.

Robert Bardo hired a Tucson detective agency to find the object of his obsession, Rebecca Schaeffer, one of the stars of the situation comedy “My Sister Sam.” The agency turned to a California subcontractor, which obtained Schaeffer’s address for a small fee from the state Division of Motor Vehicles. The agency collected $250. Six weeks later, Bardo shot Schaeffer to death at the glass security door of her apartment complex. She was 21 years old.