The first stage is the "fantasy" stage, during which the shooter only conceives of the shooting, dreams about the news coverage, and may even discuss the shooting with others. Detecting and intervening at this stage will prevent the attack. The second stage is the "planning" stage, in which the shooter may write down plans, determine logistics, and choose gear and weapons. If these planning events and products are detected and reported to appropriate authorities, intervention can prevent a shooting incident. The third stage is "preparation," which involves the shooter buying or stealing weapons. He may also warn some students or friends about the impending attack. If people who learn of these actions and intentions of the potential shooter report this information to police, the shooter can be prevented from putting his plan into action. The fourth stage is called "approach," during which the shooter has committed himself to the violent act and is heading toward the selected location, most likely carrying his weapons. At this stage, there is a chance that the shooter will encounter police, school security personnel or others who will observe his arsenal. If these witnesses report what they observe to police, the shooter may be stopped before he begins his attack. The fifth stage involves "implementation," which involves the occurrence of the shooting. The only way to prevent or limit casualties at this stage is to stop the shooter by any means, usually by force. The most significant difficulty in identifying a potential shooter at one of the early stages is that there is no uniform profile of a school shooter.