The document outlines the key elements of a crime under criminal law: actus reus, which is the prohibited act, and mens rea, which is the mental state. Both elements must exist at the same time for an offense. The Crown must prove beyond a reasonable doubt that the accused committed the actus reus with the required mens rea. Some offenses are strict liability and do not require proving mens rea. Regulatory offenses carry lesser penalties than criminal offenses.