but at the time, dna testing was still in its infancy. >> in 1986, we weren't even online. our state was not doing dna testing. although it was beginning to be done in other places, there were only a few select laboratories that did it, and it was a very, very expensive process. >> but by the time nancy ludwig was murdered, dna testing was routine. and to the surprise of investigators, dna testing proved what margarette eby's son knew instinctively, that the same man killed both women. >> i thought we had our case solved. and he said, well, the good news is we've matched your case. the bad news, we still don't -- can't give you a suspect. >> the dna profile of their killer did not match any of the known criminal offenders in the national database. >> the dna match didn't tell us who that person was.