Mrs. Preston (first name unknown) is a social worker who assigned a little girl, Nina Tremain, under the care of Thelma Price. Child Services was given custody of Nina after her temporary guardian, Mrs. Hawkins, died and the latter's daughter and landlord refused to take care of her. In reality, Nina's mother, Violet Tremain, left Nina with Mrs. Hawkins while she was in rehab because she didn't trust the system.
Price no longer had Nina because a "social worker" removed her from the home. In reality, the man was a pedophilic kidnapper already responsible for raping and murdering another girl, Susie Marshall. When Susie was found dead, Violet attended her vigil, believing she was Nina since Susie was still unidentified. Tracing Nina's chain of custody revealed her neglect by the system and the ruse used to kidnap her as well.
Mrs. Preston was interrogated, where she insisted on her union rep and apathetically admitted she didn't care to use all her energy for Nina due to her case load. The perp, Terry Jessup, was tracked and Nina was rescued. It's unknown if Mrs. Preston faced penalties for her actions. (SVU: "Dolls")