first, dave reichert was now the sheriff. now he could set priorities. even though you'd think it's the last thing a new guy would do, remind people of a failure, the murders still haunted him. >> what would you have me do if it were your daughter on the list? you would have me investigate that case until i tracked that person down. >> reichert knew that tom jenson, the sole remaining detective from the original task force, left alone to babysit the case for more than a decade, had not wavered. >> keep going. that's all you can do. keep plugging away. >> dna technology was much more sophisticated now and reichert and jenson believed that something detectives had done about a decade before, collecting dna from potential suspects, could be the key that unlocked the secret of the murderer's identity. >> knowing there wasn't that much sample left, hoping when we went for it there would be enough there to get what he needed. >> now scientists had a way to make copies of the dna. >> with this technique, you can just have a little. it's like a chemical photocop

for sheriff dave reichert, it was a day he will always remember. > the enormity of the whole thing hits you full face. >> a few months later, after two terms as sheriff, reichert ran for congress and won. his reputation as a straight shooter who finally got his man precedes him. ridgway is now in the washington state penitentiary, serving his 48 consecutive life sentences without possibility of parole. he is considered the worst serial killer in the history of the united states. >> profilers tell us they've learned some important lessons from the gary ridgway case. notably, ridgway's behavior was different from other serial killers indicating that one profile doesn't fit all. keeping that in mind may help police catch other serial killers sooner. >>> i'm stone phillips, and for all of us at nbc news, good night. don't worry, lucky, these wheat thins crunch stix will save us. [ crunch ] look! [ male announcer ] wheat thins crunch stix. try our new flavors. for strong bones i take calcium. but my doctor told me that most calcium supplements... aren't