DNA was in full use at the time. LE patting themselves on the back won't float this boat. If they sat on evidence they put others at risk. If they failed to get DNA testing ditto. The biggest tool in the world is available and even if it is small jurisdiction there are federal funds to help. They just have to ask.
This reminds me so much when Derrick Todd Lee was arrested in Atlanta for the brutal rapes and murders of women in s. Louisiana. It took one DA office investigator to act on a hunch and get his DNA. He bolted after. The US Marshall's service was contacted and he was arrested within a week. After two brutal years of hogwash. His DNA matched the crime scenes.