The thing about DNA in general in a lot of these cases is that even if they have DNA they still have to match it to someone in the system.
I wonder how many serial predators/killers would be caught if the U.S. managed to process it's absolutely mind-boggling backlog of untested rape kits. That's thousands and thousands of potential DNA samples and studies have shown that a very small percentage of men are responsible for the bulk of sexual assaults on women, but that small percentage attacks *a lot*.
"Repeat Rape and Multiple Offending Among Undetected Rapists"
http://www.davidlisak.com/wp-content/uploads/pdf/RepeatRapeinUndetectedRapists.pdf
I wonder how many serial predators/killers would be caught if the U.S. managed to process it's absolutely mind-boggling backlog of untested rape kits. That's thousands and thousands of potential DNA samples and studies have shown that a very small percentage of men are responsible for the bulk of sexual assaults on women, but that small percentage attacks *a lot*.
"Repeat Rape and Multiple Offending Among Undetected Rapists"
http://www.davidlisak.com/wp-content/uploads/pdf/RepeatRapeinUndetectedRapists.pdf