The targets included, government officials who had endorsed anti-sedition laws, judges who had convicted and incarcerated anarchists, and those who pursued the deportation of non-citizens who were implicated in crime or otherwise affiliated with movements that were considered illegal.
Specifically, the homes of the Cleveland Mayor, a Massachusetts State representative, the US Attorney General, and New York Judge Charles C. Nott.
None of the intended recipients were killed, a 70 year old New York City night watchman, William Boehner was killed when he investigated the bomb left for Judge Nott. In addition one of the bomb makers, Carlo Valdinoci, was killed while leaving the bomb intended for US Attorney General A. Mitchell Palmer.
The bombs were the plot of a group known as Galleanists, followers of Luigi Galeani, an Italian born anarchist-comunist. He advocated the use of violence to over throw capitalist governments. He and a number of his followers were deported nearly 3 weeks after the bombing, but for being a resident alien who advocated the violent overthrow of the government and authoring a bomb-making manuel, not for the bombing plot. Nicola Sacco and Bartolomeo Vanzetti were also notable followers of Galleani.
The bombs were accompanied by a pink flyer which was titled "Plain Words." The contents of the flyer read as follows:
War, Class war, and you were the first to wage it under the cover of the powerful institutions you call order, in the darkness of your laws. There will have to be bloodshed; we will not dodge; there will have to be murder: we will kill, because it is necessary; there will have to be destruction; we will destroy to rid the world of your tyrannical institutions.