|Family|| Brooke Thornburg (wife)|
Tricia Thornburg (stepdaughter; deceased)
Brian Thornburg (son with Tricia)
Josh Thornburg (son with Brooke)
Cragen and Thornburg both went to St. Raymond's University, and they frequently run into each other at functions. At some point, Thornburg married a woman named Brooke, with whom he had a son named Josh. He raped Brooke's daughter Tricia when she was eleven years old, getting her pregnant. He intimidated Tricia into saying she didn't know who the father was, and shipped her off to boarding school to keep her quiet. After Tricia gave birth, he and Brooke raised her son, Brian, together.
He had numerous encounters with SVU detectives when they testified in his courtroom. He was also well known for being harsh on predators and pedophiles, often imposing long sentences. This was revealed to actually be a product of his self-loathing due to his own pedophilia.
When Tricia was murdered, Thornburg feigned grief for his stepdaughter. Soon afterward, he was shot by an assailant, who later turned out to be a man Tricia had paid to kill him. He survived, however, and was rushed to a hospital.
Stabler and Benson grew to suspect Thornburg when they learned that Tricia exhibited signs of sexual abuse, and got a court order for his DNA. The evidence showed he was indeed Brian's biological father, and that he raped Tricia. Cragen visited the judge in hospital and told him they had DNA evidence that verified he was Brian's father. He acknowledged what he did to Tricia, but still denied that he murdered his stepdaughter to keep her quiet. It was eventually revealed that Brooke killed her own daughter after learning what Thornburg did to her. (SVU: "Justice")