I don't believe LE has ever really stated they have DNA and if they have it has only been once or twice. I know when the lead investigator, 1st Sgt Holeman, was asked if they have DNA, he stated something to the effect that almost every crime scene has DNA. IOW, he didn't state EXACTLY that LE has DNA here, but he inferred that DNA was likely found.
I've often wondered when in other cases LE states that they have DNA, why LE has been elusive with this answer. I think LE has DNA, but they just don't know if they have the killer's DNA. In a case where the killer has an injury - skin under the victims fingernails or killer's blood at the scene - or semen in the case of a rape, LE has a very good idea that this is likely the killer's DNA. 1st Sgt Holeman in that same interview stated that 'touch' DNA is a very powerful tool now. However, the problem with touch DNA is that it is, at best, circumstantial. Just because LE has an unidentified touch DNA on the victim that doesn't mean it is the killer's DNA. There could be an innocent reason for that DNA to be there. That person touched them by accident in a store or restaurant, they picked up the victim's sweatshirt off the floor and handed it to them or any other number of reasons that have nothing to do with the crime. And LE may have more than one unidentified touch DNA.
LE can have an entity such Parabon Labs work up a facial profile of the unidentified DNA. But what good would it do if the face belongs to the guy behind the counter of a store who was at work when the murder took place?