Over 15 posts I think so link away.
What is the key data point that precludes Darlie as offender?
Personally, it's the sock. Not so much because it doesn't fit. Former FBI agent Brantley and Tom Bevel both testified about why that sock would be there. Brantley's theory was the sock could have been placed there to dispose of it. In order for that to be the case Darlie would have needed a reason to think the sock would incriminate her in the first place. The sock did come from her house but so did the murder weapon and she made no attempt to dispose of that. And yes, the sock did eventually show that her DNA was on the sock but in order for Darlie to have feared that possibility she would have needed to know that DNA could be detected in sources other than blood such as saliva or skin cells. Darlie doesn't strick me as being all that intelligent nor is there any indication she had even a remote interest in things like DNA or crime scene investigations. Plus, she was highly familiar with that neighborhood. If she wanted it disposed of and never found I'm fairly certain she wouldn't have left it laying out in the open.
Tom Bevel had an alternate theory that Darlie planted the sock there to stage the scene. As part of staging the perpetrator will typically break things, move things, hide things, etc and then weave them into his or her story. Using the sock as the staged item she wanted to use to bolster her story she would have said something like... I remember there was a sock on the hand he was holding the knife with, he put a sock in my mouth or I saw him grab a sock in the laundry room as he was leaving the house... Then when the sock is found she will hope the cops view it as a piece of evidence that confirms her story. The problem is she never mentioned the sock at all. I don't think Darlie would have taken such a huge risk to plant it and then not bring it up.
Since neither theory seems to fit I'll revert to if she planted it how did she do it? Damon had only nine minutes to live after he was attacked so that is our timeframe. Darlie was on the phone for 5 minutes 38 seconds (it should be noted that the entire time she was on the phone she was in the presence of Darin, office Waddell or officer Walling so no staging could have been done during that time). A paramedic testified Damon died roughly 1 minute after he arrived. 6 minutes 38 seconds minus 9 minutes is 2 minutes 22 seconds.
In that 2 minutes and 22 seconds she would have needed to go 150 yards round trip to put the sock there, clean the countertop, clean the floor, run the vacuum cleaner across the kitchen floor, wipe off a bloody handprint on the couch, put her own blood on her pillow and blanket, deposit a bunch of wet rags in the living room and hallway, break a wine glass on the floor and then pick up a few pieces and put them in an ice bucket and the tabletop of the wine rack without getting any blood on those pieces. I have trouble believing she could have done all those things in that amount of time.
There seems to be no explainable reason why she would take the sock down there nor does seem to be enough time for her to do it in so we have to consider what else could explain how the sock got there. And intruder discarding it there after he fled the scene seems to be the most reasonable explanation.