I don't think that any momento gathering will take place any time soon, as these crime scenes need to be preserved. But at some point, LE will likely hand the trailers back over the the families- I don't know if the trailers will have been cleaned at that point- and it will be nice if they haven't been looted or snooped in. Again, though, that's a secondary (or perhaps even tangential) objective of hauling the trailers away. The main objective is to hold them as evidence.
I understand that you have a theory for this specific case, and I don't mean to insinuate that you distrust LE as a whole. I just think that your theory might be preventing you from processing this specific quote objectively.
It doesn't seem hinky to me, a person who doesn't have a theory regarding LE involvement. It seems really, really, super duper normal.