the witness, washburn.were scattered all over the country, with the fbi's help one by one she tracked them down. >> i knocked on the door and told them we were investigating a cold case and we would like to eliminate you as a potential suspect. we had in total about 160 people we get samples from. >> 160 samples. they all needed to be compared to the dna samples from the crime scenes. easier said than done. this would take months. no idea if any of it would pay off. >> coming up. a year of dead ends and then came the phone call. >> no way. >> when dateline continues. tel o target the source of pain with nonsteroidal anti-inflammatory medicine directly at the source. voltaren, the joy of movement. everybody wants super straight, super white teeth. they want that hollywood white smile. new sensodyne clinical white provides 2 shades whiter teeth and 24/7 sensitivity protection. i think it's a great product. it's going to help a lot of patients. [♪♪] looking for a moisturizer that does more than just moisturize