There are two main categories of crime: property crime and violent crime:
Property Crimes: A property crime is committed when someone damages, destroys or steals someone else's property, such as stealing a car or vandalizing a building. Property crimes are by far the most commonly committed crime in the United States.
Violent Crimes: A violent crime occurs when someone harms, attempts to harm, threatens to harm or even conspires to harm someone else. Violent crimes are offenses which involve force or threat of force, such as rape, robbery or homicide.
Some crimes can be both property crimes and violent at the same time, for example carjacking someone's vehicle at gunpoint or robbing a convenience store with a handgun.
Omission Can Be a CrimeBut there are also crimes that are neither violent nor involve property damage. Running a stop sign is a crime, because it puts the public in danger, even though no one is injured and no property is damaged. If the law is not obeyed, there could be injury and damage.
Some crimes can involve no action at all, but rather not taking action. Withholding medication or neglecting someone who needs medical care or attention can be considered a crime. If you know someone who is abusing a child and you do not report it, under some circumstances you could be charged with a crime for failing to act.
Federal, State and Local LawsSociety decides what is and is not a crime through its system of laws. In the United States, citizens usually subject to three separate systems of laws - federal, state and local.
Federal Laws: Federal laws are passed by the U.S. Congress - House of Representatives and Senate - that apply to everyone in the United States. Sometimes federal laws may conflict with state and local laws. When there is a conflict, generally the federal law will prevail.
State Laws: State laws are passed by elected legislators - also known as lawmakers - and can vary widely from state to state. Gun laws, for example, can be greatly different from one state to another. Although drunk driving is illegal in all 50 states, the penalties for driving while intoxicated can be very different between states.
Local Laws: Local laws, usually known as ordinances, or passed by the local county or city governing bodies - commissions or councils. Local ordinances usually control how residents are expected to behave in the community, such as slowing down in school zones and disposing of trash properly.
Ignorance of the LawUsually someone has to have intent to break the law in order to commit a crime, but that is not always the case. You can be charged with a crime even if you don't even know the law even exists. For example, you may not know that a city has passed an ordinance banning the use of cell phones while driving, but if you are caught doing it, you can be charged and punished.
The phrase "ignorance of the law is no exception" means that you can be held liable even when you break a law that you didn't know existed.