A person is legally accountable for the conduct of another when:
(A) Having a mental state described by the statute defining the offense, he or she causes another to perform the conduct and the other person in fact or by reason of legal incapacity lacks a mental state;
(B) The statute defining the offense makes him or her so accountable; or
(C) (1) Either before or during the commission of an offense and with the intent to promote or facilitate the commission, he or she solicits, aids, abets, agrees or attempts to aid, the other person in the planning or commission of the offense.
(2) However, a person is not so accountable unless the statute defining the offense provides otherwise, if:
(a) He or she is victim if the offense committed;
(b) The offense is so defined that his conduct was inevitability incident to its commission; or
(c) Before the commission of the offense he or she terminates his or her effort to promote or facilitate the commission and does one of the following: wholly deprives his or her prior efforts of effectiveness in the commission or gives timely warning to the proper law enforcement authorities or otherwise makes proper effort to prevent the commission of the offense.
(ILCS Chapter 720, Act 5, § 5-2) (1981 Code, § 42.05, 5-2)