I have thought of this too, that they are so vague about DNA that it could just mean it is the girls' DNA, etc. I then think well the perp has to have a pretty good idea whether he left DNA so it is not going to fool him. I mean the perp could be unsure but there is a good chance he knows with regard to semen, saliva, blood, etc. whether he left any. The length of time it has been makes one wonder how much, if any, good quality DNA they have of the perp.
Then on the other hand, how are they clearing people including being sure the first sketch is not the person if not by DNA? An ironclad alibi is possible but how would they even know the person that has that is the person in the first sketch...? DNA seems to be the only positive way...
My apologies if this is redundant, it is a fast moving thread. I am always at least a few pages behind and have not even checked other cases lately in trying to keep up with this and one other one.