All shootings are preventable, despite common belief. Shootings frequently occur in or near the same locations, involve individuals with previous criminal histories, and are more likely to occur in evening and late hours. Often someone, a friend, acquaintance, or even family member, knows an event may be about to occur. This is frequently true in the case of mass and school shootings, as studied by the Secret Service. Exposure to violence and trauma also increases the likelihood of future violence, mental health and substance use conditions.