S2·E12 The Widow and the Wolf/Unicorns and Alligators

After the murder of her aunt goes cold, a woman helps launch Citizens Against Homicide, an advocate group that brings awareness to cases that have gone unsolved. And police solve a young girl's rape and murder when the car where her body was discovered acts like a refrigerator, preserving half of her body and allowing authorities to recover incriminating DNA from semen in her body.