Violent crimes American poetry 1 Columbine High School Massacre, Littleton, Colo., 1999 1 Firearms 1 Firearms ownership 1 Gun control 1 Illegal arms transfers 1 lisää ... Life change events 1 Mass murder 1 Police 1 Sandy Hook Elementary School Massacre, Newtown, Conn., 2012 1 School shootings 1 Siblings 1 Virginia Tech Shootings, Blacksburg, Va., 2007 1 Women detectives 1 vähemmän ...