Presumption of culpable mental state shifts burden to accused to prove absence of such mental state beyond reasonable doubt. Section 135 creates a rebuttable presumption that a requisite culpable mental state (including intention, motive, knowledge, or belief or reason to believe a fact) exists in prosecutions under the Act, while permitting the accused to establish as a defence that such mental state was absent; it specifies that a fact is proved only when believed by the court beyond reasonable doubt.