A person is guilty of a class B felony if:
I. Believing that an official proceeding, as defined in RSA 641:1, II, or investigation is pending or about to be instituted, he attempts to induce or otherwise cause a person to:
(a) Testify or inform falsely; or
(b) Withhold any testimony, information, document or thing; or
(c) Elude legal process summoning him to provide evidence; or
(d) Absent himself from any proceeding or investigation to which he has been summoned; or
II. He commits any unlawful act in retaliation for anything done by another in his capacity as witness or informant; or
III. He solicits, accepts or agrees to accept any benefit in consideration of his doing any of the things specified in paragraph I.