Seems that Wikipedia is a better starting point: https://en.wikipedia.org/wiki/Poisoned_candy_myths https://en.wikipedia.org/wiki/Poisoned_candy_myths I would

Seems that Wikipedia is a better starting point: https://en.wikipedia.org/wiki/Poisoned_candy_myths https://en.wikipedia.org/wiki/Poisoned_candy_myths I would date my understanding of the myth to be from 1980, informed by a friend's mum, so the myth was oral tradition by then, across the pond in the UK. So a handful of years after 1974 the meme had spread. This had morphed into an 'only in America' story for those of us outside the U.S. - we believed this happened on a regular Halloween basis in America and was part of 'trick or treating' (itself more American than British). Imagine the image of 'gun mad' America harbouring such 'psychos' in the community, this was easy to do if you had never been to the U.S. The idea of a razor blade in some type of sweet did do the rounds, again in the 'made in America' context, with the myth spreading verbally. As children adults would tell you but you took reassurance that there were no crazies like that where you lived, again, only in America. Sweets given to you as a child could be of variable quality. Sweets with a clove in the middle do exist, I think at the time I would have preferred the razor blade option, cyanide would have tasted better. Sweets kept past their sell by date might not be too good either, old folks could hand you these and expect you to enjoy them. So 'trick or treat' was actually part of the deal with all sweets offered by neighbours and other people you were to meet. It was therefore imaginable for the American myth to be true.