(a) Every person concerned in the commission of a crime is a party thereto and may be charged with and convicted of commission of the crime.
(b) A person is concerned in the commission of a crime only if he:
(1) Directly commits the crime;
(2) Intentionally causes some other person to commit the crime under such circumstances that the other person is not guilty of any crime either in fact or because of legal incapacity;
(3) Intentionally aids or abets in the commission of the crime; or
(4) Intentionally advises, encourages, hires, counsels, or procures another to commit the crime.