>> the lieutenant made a big joke out of it and told the rest of the squad that if i went over to the lieutenant's house and cleaned out the lint trap in his dryer we could probably clear out all the cases in the city of atlanta. >> still, buffington sent the fibers to the state crime laboratory. a young forensic scientist, larry peterson, took a look. so why was the a fiber that was stuck in the crack of a shoe, why was that important? >> because it was somewhat loosely there. people normally don't have tufts of carpet fibers stuck loosely in their shoe. >> from those few thin threads, peterson would begin to build a case to try to catch a killer. how many fibers across the board did you look at every day in this case, when the case really started getting busy? 100? 500? 1,000? >> literally there's going to be hundreds if not thousands of