>> fingerprints revealed the woman was 29-year-old summer lee baldwin. a single mother of four children. of who had a previous arrest for prostitution. >> she was a young lady that was struggling, like many of those young ladies do. they're just struggling to make it from day to day, caught up in a world that sometimes is very impossible to get out of. >> finding summer's killer wouldn't be easy. her profession meant dealing with lots of unsavory people, and any clues left in the landfill would be difficult, if this make and model was sold only in walmart stores. >> i go to walmart. i found the suitcase, same suitcase, same upc number in it, an employee there told me that they were going to be able to track any purchases made on that upc number with their system. walmart had a pretty sophisticated tracking system. >> investigators learned an identical suitcase was sold on the day summer was murdered. at 3:00 in the morning. the same customer also bought something else. >> it's not common to go shopping at 3:30 in the morning for suitcases and when you co