Is someone who causes another person to sin liable for that sin as if he did it himself?
(Please also consider someone scheming, who intentionally plays stupid people, causing them to kill each other.)
Do you know Talmud and Torah citations?
I have heard many times that one who can prevent another from sinning but does not do so, is held responsible for the sin. Kal v'chomer someone who intentionally causes a sin.
However, in such a case, the person bears no fiscal liability.
Yishai brought a parallel case from Hilchos Eidus 17:7. There it states "השוכר עדי שקר להעיד לחברו--פטור מדיני אדם, וחייב בדיני שמיים" - "One who hires false witnesses is free from punishment in human courts but liable in the Heavenly court."
Similar rules will apply to similar cases.