Patricia "Tricia" Thornburg was the daughter of Brooke Thornburg, the stepdaughter of Judge Walter Thornburg, the older half-sister of their son Josh and the biological mother of Thornburg's son Brian. Her biological father left her and her mother when she was five, her mother got a job where she met Judge Thornburg. The two got married soon afterward
History
When Tricia was eleven, Thornburg had sex with her and got her pregnant. He then shipped her off to a boarding school to keep her quiet. After she gave birth, he and Brooke raised her son Brian as their own. Upon returning from boarding school, Tricia began acting out, sleeping around with other men and getting in trouble with the law, both as a cry for help and as a way to embarrass Thornburg.
Eventually, Brooke confronted Tricia about her behavior, and Tricia told her mother that Brian was her and Thornburg's child. Enraged, Brooke hit her daughter over the head with a bottle, killing her. Soon afterward, a man Tricia paid to kill Thornburg shot and wounded him. (SVU: "Justice")