State cases involve a violation of state law and are heard in state court, while federal cases involve a violation of federal law and are heard in federal court. There are some criminal offenses that can be prosecuted in either state or federal court, or both, such as certain theft and drug-related offenses, and there are crimes that can only be prosecuted in federal court, such as mail fraud, drug smuggling and other offenses that cross state lines or international borders. Generally, the penalties for a federal offense are harsher than the state penalties for a comparable offense.