This damn flashlight argument again.
First, show me one credible source that says the batteries and flashlight were wiped?
Second, because no identifiable prints were found, doesn't mean it was wiped
Third, It has a knurled grip surface, I wouldn't expect prints on the handle.
Fourth and final, If it was wiped it was probably because it was used as the murder weapon. You'd want to take that thing right apart and wash every piece separately to ensure no blood, hair or skin was in any of the crevaces.