The generally accepted common law principle (codified in §20 of the California Penal Code) with respect to statutory prosecutions in effect at the time of this case was that, in the absence of criminal negligence, all criminal offenses require both a criminal act and accompanying wrongful intent. In 1967, the California Legislature enacted § 12031, which made it a misdemeanor to carry a loaded firearm in public. The statute did not expressly require knowledge that the firearm was loaded as an element of the crime. Dillard (defendant) was riding his bicycle on the street when he was stopped by a local police officer, Torres, who saw what he suspected was a rifle case on Dillard’s person. Officer Torres searched the rifle case and discovered a rifle containing one round of ammunition in the chamber. Dillard was charged with the misdemeanor offense of carrying a loaded firearm in a public place. At trial, he admitted that the rifle was his, and further testified that he had retrieved it from his stepfather’s home several hours earlier. The trial court excluded evidence offered in support of Dillard’s claim that he did not know the rifle was loaded at the time, and that, based on previous similar instances, he had reason to believe it was in fact not loaded. The trial court instructed the jury that knowledge of the fact that the firearm was loaded at the time of the offense was not an element of the crime. Dillard appealed his conviction to the California Court of Appeal.