You may be horrified to learn that I have served on a criminal jury before!
I appreciate you saying you are not putting me down. I know we all get frustrated trying to communicate and of course we all believe that we are being reasonable.
I do feel that I understand very well the fiber testimony and what "similar", "common source" and such mean. I also understand what you are saying---but we do disagree on the implications.
To say the prosecution needs to prove where it comes from means a criminal just needs to dispose of an item used in the crime and any fibers left behind can't be used. Of course, they can be used. There is no reason--common or not--that Danielle van Dam's unclothed body should have the same type of fibers on it found all over DW's environment. Same with the *unusual* orange fiber entwined in the wad of hair. That is my conclusion after hearing the evidence.