He was a member of the Rojas Cartel. They were rivals of the Koshka Brotherhood.
Andres is hanging out at Mateo's Bar, which is controlled by his gang, when Dexter Morgan enters the bar. As Andres and two other men look over at him, Dexter utters a single word, "Koshkas," and walks into the bathroom.
Andres sends one of his Columbian henchmen to follow Dexter, only to find that he had slipped out the window. Just then Isaak Sirko enters the bar and all their attention is drawn to him. Andres and his men try to kill Isaak, but are instead killed themselves.