In 1944, a small town in Illinois was gripped with fear that someone was spraying a toxic gas into their homes as they slept. And while there have been several explanations, there isn’t any one that’s recognized or accepted as the truth.
Research:

Behind the Scenes Minis: Piece of Work
17:48

E. Virgil Neal: Hypnotist, Fraudster, Tycoon, Part 2
41:22

E. Virgil Neal: Hypnotist, Fraudster, Tycoon - Part 1
35:28