The initial reaction by someone who has been charged with a criminal offense can sometimes be “how can I be guilty of a wrong which I did not even knowing I was committing?” This proposition can provide a defense to a criminal offense depending on the facts and circumstances of a case.
A mistake of fact is a defense where it negates the requisite state of mind required under a criminal statute. The rationale for this rule is that an accused generally should not be guilty of an offense which he had no intention of committing.
Ignorance or a mistake regarding the existence of a law is a more limited defense. In order to succeed in this regard, the accused must establish: (1) that he was not aware of the law and the law was not published or otherwise reasonably made available prior to commission of the alleged offense; (2) the accused reasonably relied upon an official statement of the law which was subsequently found to be invalid or erroneous; or (3) that he was diligent and reasonable in ascertaining the meaning or existence of an offense, honestly believed that his conduct was not a violation thereof, and a reasonable person in his shoes would have made a similar interpretation. An accused must establish this defense by clear and convincing evidence.