Hundreds of letters claimed to have been written by the killer himself, and three of these in particular are prominent: the "Dear Boss" letter, the "Saucy Jacky" postcard and the "From Hell" letter.
En centos destas cartas os autores afirmaron ser o asasino, das que máis de 200 se conservan na Oficina do Rexistro Público, e tres delas destacaron en particular: a carta Dear Boss, a postal Saucy Jacky e a carta From Hell.