Erin Russ is a standby attorney and a murderer.
At an unknown point, Russ began having an affair with a married man named Michael Gardner, who would occasionally borrow her car. Unbeknownst to her, he would use her car to seek out women to rape.
After Gardner is arrested by Detectives Benson, Stabler, and Fin for the rapes, she is called in to defend him, saying that the only reason his fingerprint was at the scene was because he walks his dog around the neighborhood. However, A.D.A. Cabot also tells him how his last victim was able to get a look at his face. After Gardner is identified in a lineup, Russ says to Cabot that, since they live in the same neighborhood, the victim must have saw his face before and became confused. During trial, Gardner decides to defend himself and has Russ act as his standby counsel.
Eventually, when a conviction is certain for Gardner, he goes into hiding at Russ's house. When he doesn't show up for court the next day, Russ claims that she does not know where he is. When Benson and Stabler show her proof that he raped and killed another girl, she still refuses to believe them and again claims she does not know where Gardner is. Later, Russ and Gardner get back to her home after withdrawing money. She soon finds the knife he used to attack his victims. When she confronts him with all of the evidence against him, he keeps denying everything. She flies into a rage and stabs him to death. When Benson and Stabler arrive at her apartment, she tells them that the door is open. When they come in and see Gardner dead, Russ explains what happened.