Following Sacco and Vanzetti 's indictment for murder for the Braintree robbery , Galleanists and anarchists in the United States and abroad began a campaign of violent retaliation . Two days later on September 16 , 1920 , Mario Buda allegedly orchestrated the Wall Street bombing , where a time-delay dynamite bomb packed with heavy iron sash-weights in a horse-drawn cart exploded , killing 38 people and wounding 134 . In 1921 , a booby trap bomb mailed to the American ambassador in Paris exploded , wounding his valet . For the next six years , bombs exploded at other American embassies all over the world
Wall Street bombing
Wall Street bombing
Sacco and Vanzetti