How to stop an active shooter. Having a gun of your own and the proper training to be able to effectively use it and a CCW can help in some situations but when the shooter is some 30 plus stories up in a building and using automatic rifles and you're on the ground its not going to help. As it is the USA is in mourning right now. An active shooter in Las Vegas just killed 59 people at least and injured over 500 from up in a building. If I was on the ground below what I would do would be to try to find cover as quickly as possible and to stay low. However, Im thinking is there any way to stop this before it happens? If you're at the hotel and you notice a suspicious individual can any actions be taken? Is there any way to know if a person is suspicious and if they might commit such a crime beforehand?