Section 20.10. Criminal liability for conduct of another; exemption

Notwithstanding  the  provisions of sections 20.00 and 20.05, a person
  is not criminally liable for conduct of another person  constituting  an
  offense when his own conduct, though causing or aiding the commission of
  such  offense,  is  of a kind that is necessarily incidental thereto. If
  such conduct constitutes a related but separate offense upon the part of
  the actor, he is liable for that offense only and not for the conduct or
  offense committed by the other person.