Here are a few things to wonder about... Isn't DW's motorhome a used one? Many of the hairs could be left over from the prior owners. How many of his children's friends have slept in it since he purchesed it?
I have been a dog owner for years... dachshunds have a similar coat to a weimaraner in length, and these short haired dogs actually shed a lot more than most longer haired dogs, and their little hairs get all over everything, in vast quantities, and are easily spread everywhere.
Vacuuming doesn't remove them, because they are too short to get sucked up by the brushes, believe me I have worn myself out trying to get them off the couch. I had to resort to an old windshield wiper (rubber blade part) to pull them out. Anyone sitting on my couch would be covered, and I had to provide throws for people nicely dressed! And I am a reasonably tidy housekeeper!!!
In dry air, these hairs just jump up on you, like a you were a balloon rubbed to attract it... It seems very logical to me that if Danielle had some of Layla's hair on her when she went into DW's house, it would be easy for some to eventually be transferred to the motorhome, especially if it is a small amount like only 100 hairs...
Also, I am curious as to when Layla would have been "blowing coat"... With our dogs here in upstate NY, it is usually in March or April, but it may be earlier out there in San Diego... if Layla was "blowing her coat", then it would have been very hard to even keep the cookie order sheet dog-hair free...
Just a few thoughts... Mr. Westerfield might have been a very tidy man, in terms of keeping things orderly in his home and motorhome, but this doesn't mean he was good at cleaning...
My husband is just like him, extremely tidy, but doesn't clean that carefully! ....Having his shoes, etc. lined up "just so" soothes his soul, but the dust bunnies under the bed are just not worth organizing! LOL!
And middle-aged eyes do not help, as the ability to focus makes it harder to see the hairs, etc... And, vacuuming a motor home has got to be difficult, all those tiny spaces, narrow corners, and short turns..
Just my thoughts on all the hair. You can't use the pinciple of transfer of hair only to prove guilt, without understanding that it goes both ways.... and did anyone ever consider the possibility that Danielle took Layla into the motorhome when she was walking her? Or that Layla went in while being walked, and Danielle had to go in to get her...
Also, while we are on the subject of dog scratches! My dogs now are about Layla's size, and when they jump up and scratch, while they do not break the skin and make it bleed right away, it can hurt like heck! Like a burn almost... and within a few hours or a day, even though blood was not drawn, a scab will form, and kids are known to pick scabs, especially kids who have nervous mannerisms like nail-biting and nose-picking!
Just tossing out my years of experience with raising kids and dogs... it was blood and hair everywhere, and no matter how hard I tried to keep up with it all, I am sure if I were accused of a crime, they would still find enough evidence hanging around to try to make something of, even though my youngest of four is now going on 30!
I couldn't agree with you more!