At common law a trespass was not criminal unless it was accomplished by violence or breached the peace. Some modern statutes make any unlawful entry onto another's property a crime. When the trespass involves violence or injury to a person or property, it is always considered criminal, and penalties may be increased for more serious or malicious acts. Criminal intent may have to be proved to convict under some statutes, but in some states trespass is a criminal offense regardless of the defendant's intent.
Some statutes consider a trespass criminal only if the defendant has an unlawful purpose in entering or remaining in the place where he has no right to be. The unlawful purpose may be an attempt to disrupt a government office, theft, or ARSON. Statutes in some states specify that a trespass is not criminal until after a warning, either spoken or by posted signs, has been given to the trespasser. Criminal trespass is punishable by fine or imprisonment or both.