Sheldon Kerrick (alias Robert Sawyer) was the main antagonist of the Law & Order: Special Victims Unit episode "Name".
Sheldon was a sadistic pedophile and murderer who first killed a businessman named Robert Sawyer in 1968, took his identity, and became a plumber. In New York in the 1970s, he supposedly killed a Hispanic boy; almost 30 years after the boy's killing, his name has not been identified and was dubbed 'The Boy in the Box'. Kerrick forced his assistant, teenager Carlos Guzman, to help him kidnap and kill four Hispanic boys in 1978. If Carlos didn't help, Kerrick would kill Anna Gable, the girl Carlos loved; Kerrick was already drugging and molesting Anna, which made her a drug addict in her adult years. After murdering the four boys, Kerrick presumably stopped and made Carlos believe Anna was dead and made Anna believe Carlos was dead.
In 2005, one of the murdered boys from 1978 was found in a construction site. Through further investigation, Detective Stabler and a fingerprint technician named Millie Vizcarrondo found Anna, who told them about Robert Sawyer and Carlos. Police found more bones buried at the Sawyer house. Comparing Sawyer's fingerprints from a 1964 misdemeanor to the prints on the bodies, Stabler and Vizcarrondo found that it wasn't the same person, and found out that the real Sawyer disappeared or died around 1968, and that the new prints belonged to Sheldon Kerrick.
Kerrick, now an old man suffering from end-stage pancreatic cancer which will end up killing him soon, was arrested. ADA Novak gave him a deal to identify the Boy in the Box; in return, he would be treated by an oncologist before his release, and he will die a free man, but if not, he will spend the rest of his life in prison, however short that might be. Kerrick claims he doesn't remember who the boy was. It is presumed that Kerrick was imprisoned and died of his cancer shortly after.