Per RL, searchers asked permission to search his property that evening. We don't know what part of his property they wanted to search, but it would seem they'd search the parcel between the cemetery and the creek. IMO, there are only two reasons I can think of the girls weren't seen in the dark: either they weren't there, or they were hidden somehow (by leaves/debris?) and not readily visible with flashlights. (For example: If you've ever seen anyone wearing camo in the woods, even in the daytime, this makes sense. You can be within a very short distance and if the person is staying still, no movements, you can't readily see them.) Others might think of other reasons they weren't seen that evening?
LOGAN: Yes, that`s true. I did not find out about it until after about 6:30 PM in the afternoon. People stopped here and asked for permission to go back on my property and said two girls were missing, and that`s the first I heard about it. It`s been a -- it`s been a -- OK.
Source:
http://transcripts.cnn.com/TRANSCRIPTS/1702/20/ptab.01.html