If they have DNA from Jackie's case, from the perpetrator, then Investigative Genetic Genealogy (IGG, also seen as Forensic Genetic Genealogy) can solve this crime. Have the police force involved got the DNA uploaded to GEDmatch at all, do we know if any work has been done on that aspect of things? There are groups out there who can do this work - I took a course in IGG last year. More interesting than I can ever say - through Ramapo College in New Jersey. They might be willing to look at the DNA matches to see what they can find, plus there are other organizations that can also help including WolfPack DNA (I volunteer for them). IGG is a useful tool to help with these cases as well as bringing something to help the family have answers. Because 'closure' is not the right word for this process because you get answers rather than closure.