Brenda Nix is a New York neighbor and witness to the crimes of Charlie and Billy Baker, which her husband Renny refused to be of much help with. She saw the car the brothers were driving and was taken to the precinct to identify it by its features in a computer program.
Entering the details, she confirmed it was a Ford Contour, which the brothers' father Al reported stolen, and it eventually proved crucial for the brother's arrests and convictions. (SVU: "Dominance")