Law & Order: Special Victims Unit

Mercy (4x14)

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When the body of a baby girl is found inside a cooler, the detectives need to investigate just who she is, and how she got there. They soon learn that the little girl had a genetic disorder known as Tay-Sachs disease, and that her name is Sarah Brown, and she is the only daughter of Andrea and Daniel Brown. When Andrea admits to having killed her daughter, Alex has to put aside her own feelings of sympathy to prosecute Andrea Brown for the murder of her daughter.