Marlene worked as a cocktail waitress in a club owned by Gianni Moretti. They started having an affair when eventually she wanted him to dump his wife for her. Moretti sent Vincent DeLuca, one of his enforcers with orders to shut her up. DeLuca stabbed her multiple times in the back with a kitchen knife while her son was outside playing. He was the one who found her dead body. (“The Fix”)
A file marked "Elias M." containing a photo of her dead body in it, as well as the knife that was used to kill her, was stolen by Sam Latimer's ring and was brought to Elias by Latimer. (“Mission Creep”)
After the evidence box was stolen from county lockup on behalf of Elias, the Marlene Elias case became a lead in Detective Carter's investigation on Elias.
In 2011, after stealing the case file on Marlene's murder, her son discovers that Vincent was her killer and murders him with the same kitchen knife he used to kill Marlene to get revenge for her death. (“The Fix”)
After the DNA of the killer of Bernie Sullivan came back, Detective Fusco revealed that the killer had half of his DNA from Marlene and half from Don Moretti, confirming Carl was the killer. Carter later confronted Don Moretti with pictures of Marlene's murder but he was indifferent to the whole thing. (“Get Carter”)
While holding his father captive, Elias muses on what he could've become if Marlene had lived to raise him. He tells Moretti that he sometimes has flashes of memories of her, the most prominent of which is her murder. After Elias is arrested, he has his lieutenant Scarface leave an envelope containing a phone and a picture of Marlene's body for Moretti. After saying goodbye, Elias has Scarface kill Moretti and his son with a car bomb in revenge for Marlene's murder. (“Flesh and Blood”)
- The character never appeared in person in any of the episodes. Her name was only mentioned several times along with a photo of her dead at the crime scene.
- The newspaper obituary states that Carl Elias was 3 years old when his mother died. Elias himself states that he was four however. (“Flesh and Blood”)