In South Braintree, Massachusetts, two security guards were murdered during a lunchtime robbery at a shoe factory on April 15, 1920. The guards, Frederick Parmenter and Alessandro Berardelli, were shot and killed by armed robbers who made off with a significant amount of cash. The brutal nature of the crime shocked the community and led to a swift investigation. Authorities arrested Nicola Sacco and Bartolomeo Vanzetti, two Italian immigrants and self-identified anarchists, based on circumstantial evidence and their political affiliations rather than concrete proof of their involvement in the crime.

The trial of Sacco and Vanzetti began in May 1920 and was marked by significant controversy and public outcry. The prosecution relied heavily on their radical political beliefs, which led many to believe that they were convicted not for the crime itself, but for their anarchist ideals. Despite protests and pleas from supporters, including prominent intellectuals and artists, the trial's outcome remained largely unaffected by public opinion. In 1921, Sacco and Vanzetti were found guilty and sentenced to death, which sparked international outrage and debates regarding fairness in the American legal system.

As the case progressed, it became emblematic of the anti-immigrant sentiments and political repression during the Red Scare, challenging the principles of justice and fair trial. Supporters claimed that the trial was fraught with prejudices against immigrants and radicals who were wrongly targeted. Despite appeals and public campaigns advocating for their clemency, Sacco and Vanzetti were executed on August 23, 1927, further igniting discussions about the integrity of the criminal justice system in the United States.