PCA says explicitly that it was BK's DNA on the knife - not the father's!!!!
So you are right. The dad's DNA was from the trash (and likely collected before BK ever arrived back in PA - where they then probably tried to get his in the same fashion).
That's what is meant by "genetic genealogy in this case."
Well, I call it a knife pocket because it's where my dad and uncles carried knives, in jackets like this. The last photo on the page shows the interior pocket. We don't know the exact size of the Ka-Bar knife, but I am assuming it's the one with the 7" blade. I think there are other jackets with a similar design with larger pockets, though it's possible the 11.5 Kabar would fit on the diagonal there.
Or just stick it in the exterior lower pocket.
I actually think BK was into cosplaying military style and was likely a gamer (SPECULATION ONLY, although there are clues). So this jacket has ample exterior pockets if concealment and easy access is wanted and while I can't see the size of the interior pockets, they are described as "cargo" pockets, meaning large.
I think he would have used just the hand warmer pockets in this crime, in any case (but could conceal his weapon on his person in interior pockets when he was out and about).
I believe he practiced taking a knife with him to public and other places, as part of prep for this crime. IMO.
Carhartt is my winter attire, usually worn with a few other layers.
Most winter clothing has tight cuffs and if it didn’t fit in a pocket, it could have been carried in a sleeve.
I’m a bit of a pack rat and tend to fill my pockets with mystery items but I have been known to carry larger tools and such in my sleeves for short periods of time.
I also agree that he must have practiced handling and carrying the knife.