The defence doesn't have to say what it was once it's proven not to be blood.
The prosecutions own expert said a TMB negative means it's not blood.
Why is this so hard to understand?
It is not proven that it's not blood. Like Otto, Amber, and others have stated, TMB can come up negative after Luminol is applied, even if is blood. Its sensivity is less than that of Luminol, and also Luminol further deteriorates the matter to be tested, making it even harder for TMB to pick up.
I see now that the whole case for innocence seems to be riding on this TMB test, thus the great importance attached to it and emphasis on it.
I am surprised that as to why do the supporters of her innocence even acknowledge that those are Amanda's footprints? Why not say they are not hers? That would be much simpler, IMO.
Because it seems like everything else has been excused excused excused away, and these footprints are the only thing which cannot be excused away, therefore the constant reiterations of TMB negative, and the far-flung theories of bleach residue (managing to stay active for how long?), the beet juice, fruit juice, cat blood, etc..
These nagging footprints. Why not just deny that they are Amanda's? Why not just say they were Meredith's from before she was murdered, perhaps from earlier that day? Or is that even too far-flung for the innocence theory?