(1) A person commits the crime of tampering with physical evidence if, with intent that it be used, introduced, rejected or unavailable in an official proceeding which is then pending or to the knowledge of such person is about to be instituted, the person:\n(a) Destroys, mutilates, alters, conceals or removes physical evidence impairing its verity or availability; or\n(b) Knowingly makes, produces or offers any false physical evidence; or\n(c) Prevents the production of physical evidence by an act of force, intimidation or deception against any person.\n(2) Tampering with physical evidence is a Class A misdemeanor. [1971 c.743 §204]
Oregon Legal Code