Los Angeles in 1942 was a pressure cooker. Pearl Harbor had thrust America into war eight months earlier, and Southern California's defense industries were drawing workers from across the country. The Japanese American internment, ordered by Executive Order 9066 that February, had removed 120,000 people from the West Coast. The resulting agricultural labor shortage brought the Bracero Program, importing Mexican workers on contracts. Racial tensions simmered. The Los Angeles City Council appointed a grand jury, headed by E. Duran Ayres, to investigate an alleged 'Mexican crime wave.' Into this volatile atmosphere came the death of a 22-year-old at a reservoir party.

Diaz's autopsy revealed he was intoxicated with blunt head trauma and stab wounds, but the coroner could not determine a cause of death. It might have been a fall, an automobile accident, or an assault. None of that mattered to the LAPD. Within days, they arrested Henry Leyvas, 20 years old, along with 24 members of what the media termed 'the 38th Street gang.' On August 10, police conducted a mass roundup of 600 Latinos charged with suspicion of assault, armed robbery, and related offenses. The newspapers screamed for action against 'zoot suiters.' Seventeen young men would stand trial for murder in a proceeding that would shock observers.

Judge Charles W. Fricke presided over what is now recognized as a trial lacking fundamental due process. He permitted E. Duran Ayres to testify as an 'expert witness' that Mexicans as a community possessed a 'blood-thirst' and 'biological predisposition' to crime and killing, citing the culture of human sacrifice practiced by their Aztec ancestors. On January 13, 1943, twelve defendants were convicted of second-degree murder and sent to San Quentin Prison. Five others received lesser charges. The Sleepy Lagoon Defense Committee formed, bringing together activists including Orson Welles and Eleanor Roosevelt. Actor Anthony Quinn raised money for the defense after his mother reminded him of eggs once given to their family by the mother of one of the accused during a time of poverty.

The convictions ignited outrage in the Mexican American community. Rumors spread that gang members had attacked Navy servicemen. In June 1943, sailors and soldiers rampaged through Latino neighborhoods, attacking anyone wearing a zoot suit. The violence lasted ten days and became known as the Zoot Suit Riots. Meanwhile, attorneys including Carey McWilliams and Robert Kenny challenged Judge Fricke's handling of the case. In October 1944, the California Court of Appeals unanimously reversed all twelve murder convictions in People v. Zammora, finding the evidence insufficient and criticizing the trial judge's bias. The young men walked free. The case became a symbol of institutionalized racism in wartime America, later immortalized in Luis Valdez's 1979 play Zoot Suit and the 1981 film adaptation.