Showrunner Elwood Reid said that they have a specialist 'autism consultant' (Alex Plank) for Diane Kruger's character, Sonia. He is on set and will comment on every script and episode.
Diane Kruger has said that she would not have received her role as Sonia for a movie, as characters with Asperger's would never be allowed the lead, but are "...often used as comic relief, or as the odd guy that shows up every once in awhile."
Diane Kruger claimed that one of the great appeals of TV over movies for her is that it offers the most meaningful roles for women.
In series 1 episode two (Calaca) when Steven asks his coworker what has been going on she answers "big Johns talking about the river again and EmmyLou and not taking his meds" direct reference to Neil Youngs song Powderfinger " Big John's been drinking since the river took Emmy-Lou"