Quirino Ernesto Paulino Castillo, a.k.a. "el Don" (born 8 September 1960 in Comendador, Elías Piña Province) is an ex-captain of the army of the Dominican Republic, and alleged boss of a drug-trafficking organization responsible for importing tons of cocaine into the United States since September 2003. Castillo's personal fortune was estimated at $2 billion dollars.