I think it was speculated that the homes searched belong to RSOs, but not reported as such or confirmed.
Personally, I think the motive for this crime was sexual assault so I believe there is a high likelihood that DNA was left behind. I'm just not so sure it matches anyone in the database. I think LE has a DNA sample that they can't match, but that's just my opinion.
You may very well be correct. If you're right then we can assume that there will be no search warrants executed at the homes of RSO's ( regardless of whether they have done this in the past ) because they will already be cleared by DNA evidence. Even without a match dna at leasts narrows the field, even if only by a little bit. Makes me wonder if LE will resort to asking all men in Delphi to voluntarily submit a sample.