Situational awareness is one of the most important components of self-defense. Recognizing potential threats early gives you more time to avoid danger, make good decisions, and act before a situation becomes a crisis.

There is no single profile of a mass shooter, but U.S. public mass shooters are overwhelmingly male, and roughly half are White. Handguns are the most commonly used firearms. There is no prominent religion, political affiliation, or ideology. Grievances, personal crises, suicidal behavior, threats, and other warning signs are generally more useful indicators than race, religion, or politics.

California law recognizes justifiable homicide as the lawful use of deadly force when a person reasonably believes it is immediately necessary to defend themselves or another from an imminent threat of death or great bodily injury, or in certain limited situations involving violent felonies or authorized law enforcement actions. The force used must be reasonable and no greater than necessary, and the justification ends once the imminent threat has passed.