Various events took place in Puerto Rico during the 1930s thru the 1950s , involving the Puerto Rican Nationalist Party and the local government which influenced Margenat 's political views and his way of thinking . The Río Piedras massacre on October 24 , 1935 , a confrontation with police at University of Puerto Rico campus in Río Piedras , in which 4 Nationalist partisans and one policeman were killed . On February 23 , 1936 , two Nationalists named Hiram Rosado and Elías Beauchamp , were arrested , transported to police headquarters , and executed within hours without trial for the murder of U.S. appointed Police Chief Francis Riggs . No policeman was ever tried or indicted for their deaths . On March 21 , 1937 , a peaceful march organized in the southern city of Ponce by the Puerto Rican Nationalist Party turned into a bloody event when the Insular Police ( " a force somewhat resembling the National Guard of the typical U.S. state " and which answered to the U.S.-appointed governor Blanton Winship ) opened fire upon what a U.S. Congressman and others reported were unarmed and defenseless cadets and bystanders alike killing 19 and badly wounding over 200 more , many in their backs while running away . An ACLU report declared it a massacre and it has since been known as the Ponce massacre . The march had been organized to commemorate the ending of slavery in Puerto Rico by the governing Spanish National Assembly in 1873 , and to protest the incarceration by the U.S. government of nationalist leader Pedro Albizu Campos . Soon thereafter , the leadership of the Nationalist party , including Pedro Albizu Campos , were arrested and incarcerated for conspiracy to overthrow the government of the United States
Ponce massacre
Ponce massacre
Hugo Margenat