Many people trace the inflection point back to the kidnapping of Etan Patz in 1979. The case was highly publicized and made many parents afraid of child predators in a way they really hadn't been before. That case and a few others led to putting pictures of missing children on milk cartons so then the fear was in their faces every day.

https://crimereads.com/how-the-disappearance-of-etan-patz-ch...