Also in 1609 rumors of an impending rebellion of Negroes circulated. Velasco took preventative measures, including sending an armed force under Captain Pedro González de Herrera to Puebla. Herrera was to combat the escaped slaves and rebels (Maroons) on the Rio Blanco, who preyed on travelers between Veracruz and Mexico City. The leader of the blacks, Gaspar Yanga, sent a letter to Captain Herrera. The letter outlined the mistreatment of the blacks that had led them to flee captivity. Velasco took cognizance of the letter, but not before a bloody battle was fought, with heavy losses on each side. Velasco then arranged for the escaped slaves to found their own village, San Lorenzo de los Negros, near Córdova.