Is it not alleged that Jeremy (if we assume he did it, or some other intruder), on the night of the murders, entered WHF through the downstairs bathroom window and exited through the kitchen window?
Now, I have no problem with someone crawling in through the bathroom window, assuming that all the lights in the house had been turned off for the night; but I do have a problem with Jeremy (or someone else) crawling out of the kitchen window after having killed everyone in the house. The kitchen was LIT when police and Jeremy arrived at the farm.
I have a problem seeing ANYONE being so stupid and careless to actually do that, the risk of being seen crawling through the window of a fully lit room must have occurred to the alleged intruder!