MODEL PENAL CODE
(1) No person may be convicted of an offense unless each element of such offense is proved beyond a reasonable doubt. In the absence of such proof, the innocence of the defendant is assumed.
(2) Subsection (1) of this Section does not:
(a) require the disproof of an affirmative defense unless and until there is evidence supporting such defense; or
(b) apply to any defense which the Code or another statute plainly requires the defendant to prove by a preponderance of evidence.
(3) A ground of defense is affirmative, within the meaning of Subsection (2)(a) of this Section, when:
(a) it arises under a section of the Code which so provides; or
(b) it relates to an offense defined by a statute other than the Code and such statute so provides; or
(c) it involves a matter of excuse or justification peculiarly within the knowledge of the defendant on which he can fairly be required to adduce supporting evidence.
(4) When the application of the Code depends upon the finding of a fact which is not an element of an offense, unless the Code otherwise provides:
(a) the burden of proving the fact is on the prosecution or defendant, depending on whose interest or contention will be furthered if the finding should be made; and
(b) the fact must be proved to the satisfaction of the Court or jury, as the case may be.
(5) When the Code establishes a presumption with respect to any fact which is an element of an offense, it has the following consequences:
(a) when there is evidence of the facts which give rise to the presumption, the issue of the existence of the presumed fact must be submitted to the jury, unless the Court is satisfied that the evidence as a whole clearly negatives the presumed fact; and
(b) when the issue of the existence of the presumed fact is submitted to the jury, the Court shall charge that while the presumed fact must, on all the evidence, be proved beyond a reasonable doubt, the law declares that the jury may regard the facts giving rise to the presumption as sufficient evidence of the presumed fact.
(6) A presumption not established by the Code or inconsistent with it has the consequences otherwise accorded it by law.