9. Wayne Williams
Wayne Williams may have "only" been convicted of killing two men in 1981, but he is also widely suspected to have been responsible for most of the Atlanta Child Murders that took place from 1979-1981, with 28 children being killed. To his part, Williams continues to maintain his innocence to this day.
We know that the Mindhunter production is seeking actors to play family members of a number of his alleged victims, as well as a number of key police officers who were involved with the case.
David Fincher has suggested that the Atlanta Child Murders will make up a significant portion of the season, and even have a direct impact on the show's shifting style:
"Next year we’re looking at the Atlanta child murders, so we’ll have a lot more African-American music which will be nice. The music will evolve. It’s intended to support what’s happening with the show and for the show to evolve radically between seasons."
It's easy to imagine how effortlessly chilling Williams' presence will be opposite Ford and Tench when they swing by for an interview.