Any attempt to establish the guilt or innocence of Sacco and Vanzetti must be based upon an analysis of the evidence against them. Both the principles of Anglo-American jurisprudence and the logic of historical inquiry compel us to declare them innocent in the absence of any convincing proof of their guilt. The vast documentation now available has enabled us to tell the story of the preparation of the prosecution's case in almost all its aspects. The revelations of the state police files, the grand jury proceeding, and the prosecution notebooks show that virtually every piece of evidence against the two men ultimately rested upon falsehoods and fabrications. The authors of this book have attempted to avoid psychological speculation and base their conclusions on concrete evidence to the maximum extent possible, but some explanation of the prosecution's conduct is clearly called for. It is impossible to know what went on inside the minds of Stewart, Brouillard, Katzmann, and Williams, but evidence leaves room for some hypotheses regarding their motives.
In May 1920 southeastern Massachusetts was preoccupied with three recent holdups: the successful stickup of the Randolph Savings Bank in November 1919, the attempted robbery of the L. Q. White payroll in December, and the double murder and fifteen-thousand-dollar robbery in South Braintree. The United States was also passing through a period of extreme patriotism and nativism, and local opinion, as reflected in newspaper comment, also viewed the growth of radical agitation with considerable alarm. In Boston a local legislator had introduced a resolution calling for a substantial reward to anyone who could find the perpetrators of the three holdups. In late April Chief Michael Stewart of Bridgewater stumbled upon a small group of anarchists and quickly concluded that he had found the Bridgewater and South Braintree bandits. After the arrests of Sacco, Vanzetti, and Orciani his conclusions were immediately endorsed by the district attorney's office.
Despite the failure of most of the witnesses to identify either bandit and despite the initial lack of any physical evidence, the district attorney's office was saying within a few days that it was certain it had found the men it was after. Prejudice seems to have played some role in Stewart's conclusions. His initial comments on the Bridgewater holdup