If not criminal RICO why not civil suits citing the doctrine of vicarious liability?
SPLC used it against Tom Metzger, et al. (white supremacist group) tying them to the murder of a black man by skinheads who were not members of the Metzger's group. The skinheads were influenced by Metzger said the suit IIRC.
Soros owns too many people to be indicted.