He is a Cuban child found hiding in The Castillos' salvage yard.
Oscar is first shown peering through a hole in the trunk of a broken down car. Oscar seemingly witnesses Dexter Morgan abduct Valerie and Jorge Castillo, and then move their bodies to his car after he kills them.
The next morning, the police hear a noise inside the car's trunk and pull their guns. When they open it, they find a very frightened boy. Maria LaGuerta reassures him in Spanish and helps him out of the car. The boy's name is Oscar, and he says that a man saved him, which makes Dexter nervous.
While Oscar works with a sketch artist describing who saved him, Maria and Oscar begin to bond, and Maria even considers adopting him. However, Oscar's Uncle Roberto is located in Tampa and he arrives to take a happy Oscar to live with him in Tampa..
Oscar's sketch is later shown to be a depiction of Jesus Christ, to the astonishment of the department, and even Dexter himself.
- Originally, the sketch depicted eyes very similar to Dexter's (especially when compared to artwork of his likeness in the Early Cuts series). After the picture is completed, the eyes have been slightly redone to resemble the usual Jesus Christ picture.