Twelve killed , Hundreds injured when police broke up a demonstration by Nationalists agitating for an indepenedant Puerto Rico , in Ponce , second city of the island . The battle grew out of contradictory orders issued by the authorities , the Mayor of Ponce , having given permission for the demonstration to take place , and Colonel Enrique de Orbeta , the Police Chief , forbidding it . Photo shows , a demonstrator dragging a wounded comrade to saftey during the battle in Ponce , Puerto Rico . 5 April 1937