Olivia Murray was a federal agent working with Immigration and Customs Enforcement.
When I.C.E. could not make progress with the investigation of the San Marcos murders, Murray's investigation was shut down. A body dragging murder gave her a new angle back into the Mexican cartel investigation and the Los Angeles scene. The dragging also launched a working relationship between her and Vic Mackey, who then repeatedly helps her make cases. When her file shows up in Cruz Pezuela's blackmail box, Mackey worked to help retrieve it.
Thanks to Vic's efforts in helping her escape Pezuela's grasp, and believing his remarks that his transgressions were blown out of proportion by jealous superiors, Olivia brokered a deal for Vic, promising him a job with I.C.E. as well as full immunity for crimes he confesses to in exchange for taking down Beltran. Though she was able to secure a deal for Vic, she was unable to do the same for Ronnie, the lone member of the Strike Team still loyal to him.
Vic then meets with I.C.E. and confesses all of the crimes of himself and the Strike Team over the previous three years: the murders of Terry Crowley, Margos Dezerian, Guardo Lima, and others, their role in the Armenian Money Train robbery, as well as Shane's murder of Curtis Lemansky. Once Vic's shocking confession is over and the terms of his deal are set, Olivia is filled with rage and disgust for a man who had up until then been playing her for a fool. She informs Vic that he had given the federal government enough to send Ronnie to prison for the rest of his life, and warns that any attempt to alert Ronnie of his status would violate the terms of the deal. Vic agrees to "string [Ronnie] along" until the bust is done.
Once Claudette learns of Vic's new deal with I.C.E., she and Dutch meet with Olivia and request that she place Corrine and Mackey's kids into the witness protection program. With this, Olivia could deliver a personal blow to Vic for tricking her into giving him the immunity deal. When Vic later learns of this development, he pleads with Olivia to let him see his kids, saying that he did not have a chance to say goodbye to them. An unsympathetic Olivia retorts that he said goodbye the moment he shot another cop in the face.
Despite Olivia's efforts to take them off the case, Vic and Ronnie successfully infiltrate Beltran's drug location. Olivia and ICE agents arrive at the scene, as well as Aceveda, who was instrumental in letting Mackey continue his mission. While during the bust the drugs are not at first visible, they are found hidden moments later, completing Mackey's immunity deal. Following the bust, Olivia sends Ronnie and Vic back to The Barn, where the former is to be arrested while the latter is forced to watch.
The next morning, Vic goes to ICE to start his new job. He again asks Olivia about where his family is but she refuses to tell him. She then breaks the news that he won't be working on the streets for ICE, but would actually be writing a ten-page report on a daily basis on gang related activity. His tasks will involve no active investigation on his part - crime data will be provided to him, and he will be required to analyze it and reach an opinion as to what the crimes reveal about gangland politics.
Vic initially refuses this desk job, but Olivia tells him that if he doesn't take the job for the next 3 years he will be prosecuted for all his confessed crimes. Likewise, he'll be prosecuted if he breaks any of the terms of his employment, which are extremely restrictive: notably, Vic is not authorized to carry a weapon on the job, and is not to have any direct role in police work. Olivia makes it clear that she will be monitoring him closely for any breach of the rules which will allow her to prosecute him and that she will see to it that she makes Vic's next 3 years working at ICE be a living hell for him. Following one last plea to let him see his children, Olivia coldly informs him that the office has a suit-and-tie dress code, and that he should go home and change during his lunch break.