Even after 40 years, there is still hope of solving a case. Eyewitness testimony is worse because memories fade, but forensic evidence is so much better than it was 40 years ago. A U.S. case from Illinois was once solved after 55 years. The family should never give up hope.
It definitely seems odd to have new variables brought into an old mystery of an equation, but I do think investigators look into the matter. With technology being better these days, especially with the use of DNA I think more mysteries have the potential to be solved. I especially think that such an enterprise is worth it because many times it seems that patterns can be noticed and similar unsolved cases can then be linked together. It always tugs at my emotions when I hear of unfortunate incidents where the evil-doer is at large, but it when one is caught and then linked to previous unsolved cases it seems at least this would bring a semblance of peace to the victims' families.
40-year cold case reopened: investigators have a hope of catching the criminal, otherwise they would not have re-opened the investigation. The reality is that technological advances have so helped the world of criminal investigations that the odds of cracking such old cases is a reality. We can expect it to only get better.
Any important DNA evidence is either unlikely to exist or questionable for its validity since there could be tampering. Forty years is too long a time to have passed. It could be that the criminal has passed away or assumed a different identity. However, DNA fingerprint science, through the CODIS system, helped to put Robert Pilcher behind bars for the 1974 murder and rape of Mary Jayne Jones. Pilcher was already under suspicion for a similar crime. Pilcher is the cousin of the barn owner where Jones' body was found. It wasn't difficult to piece the parts of the puzzle together. Modern science made it possible.This is an exceptional case. If the suspect is not registered into a database, it would be impossible to prove he committed the crime.