Other police killed marchers and bystanders at a parade in the Ponce massacre ( 1937 ) . The Nationalists believed these showed the violence which the United States was prepared to use in order to maintain its colonial regime in Puerto Rico . Historians Manuel Maldonado-Denis and César Ayala believe the motive for this repression , especially during the Great Depression , was because United States business interests were earning such enormous profits by this colonial arrangement
Ponce massacre
Ponce massacre
Pedro Albizu Campos