Deadly Force Law and Legal Definition

Deadly force is is force that creates a substantial risk of causing the death of another person. Use of deadly force to protect property is governed by state laws, which vary by state.

Under some state statutes, deadly force may be used in only three specific circumstances: (1) in defense of a person threatened by deadly force or serious bodily injury by the criminal trespasser; (2) in order to prevent an attempt by the trespasser to commit arson or any other crime of violence; and (3) when a person properly on the premises reasonably believes that deadly force is necessary to prevent or end a forcible unlawful entry into his dwelling or place of work. Local laws should be consulted for specific requirements in your area.