She is first seen working in Brian Moser's residence, where the Ice Truck Killer killed most of his victims. Dexter, still dealing with the disappearance of his sister, orders Karen to meticulously collect every bit of evidence and be in charge of it. He rapidly runs through a list of her duties. Karen asks Vince Masuka if Dexter is in charge and Masuka responds by saying, "I guess he is now."
Karen continues to reappear throughout the early seasons, usually in the background at crime scenes. She also attends Dexter and Rita's Wedding, along with most of Miami Metro Homicide.
As a background character, she is one of the few that is credited with her name (or as "Technician"), and a general title.