I didn't say it wasn't sociopathy; it most certainly was. Autism and sociopathy are not mutually exclusive. And as they were executing their plan, I do not see any point where their "autism was turned off".

Autistic people can be highly sociable by explicitly learning social skills. They can also learn social skills in order to manipulate others, as is the case here.

Lastly, explaining how a medical condition whose stereotypes seem to make others think those with it would not be capable of committing a crime were in fact capable of committing that crime in no ways is the same as excusing the crime.