Yeah, that I don’t know about.
And how did they know to go search that house if the purpose of the DNA was to match it to him? There doesn’t appear to be anything left of the RV/van to find a VIN or a license plate ID him to go look at his house.
It is also quite feasible that one of the LE had the presence of mind to note a license plate on the vehicle if he had not removed it. If there was no license plate, then it is possible that they did a data search for the type and color of the van and if only a handful of those showed up in the data base then they could quickly discover who still had their vans intact and who did not.