Other bodily functions could have been expelled too. Thanks for a closer look at that bag of bedding @whisperOFwings .
This could be the reason the items were found in the trash.

He forgot to take out the trash bin, so the items remained, so LE had access to them, plus the entire house and contents.
These certainly would provide clues, if the family were murdered while in bed.
I wonder if cadaver dogs, could pick up this scent, on the bedding, if that is the case.
If SW was murdered in bed, his theory of her strangling the girls, is thrown out the window.
MOO.