Here is just a short list of mass murder that ocurred before 1967,
http://www.americanthinker.com/blog/2012/07/mass_murder_a_modern_curse_hardly.html
http://www.americanthinker.com/blog/2012/07/mass_murder_a_modern_curse_hardly.html
...July 26, 1764 -- near what is now Greencastle, PA. Four Lenape Indians killed a schoolmaster and nine or 10 children.
December 22, 1868 -- Chattanooga, TN. Three dead following a shooting by a disgruntled student.
April 13, 1873 -- Colefax, LA. Following a disputed election, white Democrats killed an estimated 60 to 100 mainly black citizens in a disputed Democratic/Republican gubernatorial race.
December 11, 1875 -- Bremerhaven, Germany. Alexander Keith, Jr., in a plot to bomb ships and collect insurance money, had his bomb, sitting on the dock, accidentally go off, killing 80 and injuring about 200 more. He committed suicide shortly afterwards.
April 9, 1891 -- Newburgh, NY. An elderly man fired a shotgun at St. Mary's school, injuring several students. No deaths.
May 25, 1893 -- Osaka, Japan. Kumataro Kido and Yagoro Tani killed 11 including an infant. Kido had lost his common law wife to another man, so they killed him, his former wife and other family members. The two committed suicide afterwards.
March 14, 1912 -- Carroll Co. VA. Floyd Allen started a gun battle at the court house after he was convicted of taking his two nephews from the custody of the sheriff's deputies. Five were killed and seven wounded.
September 4, 1913 -- Degerloch, Germany. Ernst August Wagner killed his wife, four children and shot 20 more, with nine dying. He was found not guilty by reason of insanity.