A person who is legally accountable for the conduct of another which is an element of an offense may be convicted upon proof that the offense was committed and that he or she was so accountable, although the other person claimed to have committed the offense has not been prosecuted or convicted or has been convicted of a different offense or degree of offense, is not amenable to justice or has been acquitted.
(ILCS Chapter 720, Act 5, § 5-3) (1981 Code, § 42.05, 5-3)