ended when he returned to L.A. Owing to his distant demeanor and predilection for isolation, Charlie was unaware of this relationship. As Don's fiancée long ago, Kim Hall had a chance to come to know Don and observed that the brothers had "one part exuberance, two parts obsession," after she was assigned to a case working alongside the two. He had also once dated an ATF agent, and was pained to find out that she called him before she was killed. The prosecutor Nadine Hodges (Sarah Carter ) seems to be smitten with him and vice versa. In the episode "Guns and Roses", he decides to investigate his flirtation with AUSA Robin Brooks (Michelle Nolden ). In "Blackout," after Robin broke up with him, Don became involved in a brief romance with Special Agent Liz Warner, whom he remembers for having an issue with adrenaline and being wild. He often makes reference to the difficulties in maintaining a relationship, given his career, as does his family. Don is now actively pursuing his love interest in Liz Warner ("End of Watch"), something he has not done in a long time. She is initially hesitant about entering the relationship, especially given his reputation for short relationships. Don persuades her that they can still have an active relationship despite both being FBI agents and both working out of the L.A. Office ("Finders Keepers"). In "One Hour", Don's therapist questioned his motives concerning this relationship, and Don defended his actions. His supervisors in the FBI are aware of the relationship but the consequences have not been revealed. Finally, in the episode "Graphic," it is revealed that Don broke up with Liz, and was very depressed about it. With "In Security," Don's secrecy and his unwillingness to reveal information regarding his relationship with a woman in the Witness Protection Program, Leah Wexford (Jennifer Riker), whom he knew in Albuquerque years ago, strained his relationship with Liz. He has spoken to his father on the matter. In "Take Out," Don must see a therapist who is led to believe that he is "trigger happy." His father noted that this may be true, as he often shoots first. Further, Alan recalled how Don would take on others' burdens as a child and told him to get counseling, which he later willingly sought, especially considering that he viewed his life's work as a series of dirty deeds. In