|Family|| Unnamed first wife (deceased)|
Unnamed second wife
Susan Sidarsky (daughter with his first wife; deceased)
Ellen Sidarsky (daughter)
Unnamed daughter (fathered with his second wife)
|First Appearance||"A Single Life"|
Robert Sidarsky was a wealthy businessman and a prime suspect in the rapes of his daughters, Ellen and Susan, when they were ten years old. He buys their silence by setting up substantial trust funds in their names. After his first wife dies, he remarries and has another daughter.
When the adult Susan commits suicide, Detectives Olivia Benson and Elliot Stabler learn that she was molested by her father. Benson persuades Ellen to testify against her father by telling her that her half-sister is the same age that she and Susan were when their father abused them. The detectives arrest Robert and bring him to their interrogation room, where Ellen confronts him. He threatens to take away her trust fund, but she insists that she will send him to prison. He is then sent to prison for the abuse. (SVU: "A Single Life")