<modsnip - off topic>
What do we see in ID case: lots of locals, lots of potential suspects. Lots of people partying around the house, even. The whole case is based on one piece of touch DNA. For that DNA, as we know, a private database is entered.
Nothing is done for the DNA under fingernails.
In bacteriology, there is a word “fomites”.
“Fomites” are items of clothes or objects that have traces of a pathogen on them. It becomes important during epidemics such as plague, smallpox but many others, too, where the disease can be spread if people use the objects that the sick person has touched or used before. So it is indirect transfer not from host to host but via an object.
So this DNA on the sheath reminds me of that term, “fomite”. It is indirect transfer, not on the body, not anywhere else. Just an object lying on the bed.
While DNA under the nails implies direct contact between two people.
So IMHO, it had to be given as much attention as the DNA on the sheath. The same process, same database, trees, all had to be used.
Why it wasn’t is a question.
We just need to have better DNA laws.
All answers that I got from our participants tell me one thing: why the DNA under the nailbeds has less relevance than the DNA on an object lying on the bed
My observation is different: at the time of the crime, they were of equal relevance and should have been processed equally diligently. You don’t rule out evidence you use all of it and only later start eliminating suspects
JMO of course…