Luis Ramos is the living son of Maria Ramos, who lost his brother and her son Miguel to hitman Eddie Fuentes at the direction of Maria's abusive boyfriend, drug dealer Fredo Garcia. Maria and Luis went into hiding, but Luis was found through a family friend named Annie Colon, who was providing the family sanctuary.
Luis was taken into custody and refused to divulge his mother's location, but she was found, and both of them were distraught from finding out Garcia got Miguel killed. Both are scared to testify, especially after Fuentes tries to shoot them both and detectives but only wounds Marie's arm.
After Marie nearly shoots Garcia dead herself, she and Luis are absolved of charges and placed into witness protection, where Luis can continue with school and Marie doesn't struggle with access to resources. (SVU: "Protection")