sentences:  Among Soto's most famous works are "Spiks", which deals with the struggles he and many other Puerto Ricans faced in New York, and "Usmaíl", a story set in the Puerto Rican island of Vieques in the early 20th century.Soto was a supporter of the Puerto Rican independence movement, a theme that often shows up in his books.On July 25, 1978, one of his sons, Carlos Soto Arriví, was killed by police officers in the Cerro Maravilla Incident.