We are talking about footrints matching Amanda's feet on ascene where a crime occurred and where there are isolated bare footprints in diluted blood.
There is half a footprint on the bathmat in diluted blood.
There are other footprints detected with luminol which tested negative for blood. They
could be blood, but nobody including you knows.
They
could have been made on the night of the murder too, but nobody including you knows whether that's the case or not either.
These footprints form a system showing non-random features.
Footprints all around the house, footprints forming a trail wpuld be a random artifact. It is not likely that only part of the trail is cleaned as thye wash the floor, because usually, in a normal routine, people clean the hole floor, not pieces of floor here and there. If part of the trail was cleaned in an operation of cleaning only part of the floor, you would see footprints cleaned by half, pieces of footprint left and remains.
The artifact in question doesn't have this random features, by which we could try to link it to "old" remains of normal operations. You cannot assert that you can expect to randomly find isolated footprints of a right-foot reacting to lumiol, and overlook any need of explanation for it.
Do you have a citation for this rule, or is this something you just made up?
What properties do you believe every possible non-blood reactant has that blood does not, so that blood can leave a short trail of prints but no other substance can?
Moreover the finding shows multiple footprints in Amanda's room, and no other similar "random artifact" in other rooms in the house.
What do you conclude from this?
About the TMB test, the fact is all literature says it shall not be used as confirmatory test, nor posively neither negatively. The TMB test used in this case is indirect, it requires the collection of a liquid sample from the stain, and this operation is itself an information filter. You know that Mederith's DNA did show in some of the luminol artifacts, and was also mixed with Amanda's. Some are in places where they should not be, like Filomena's room.
In a shared household, especially one where multiple people have recently been in and our of Filomena's room, there is no basis for claiming that Amanda's DNA on Filomena's floor is evidence of anything.
How would you expect to find Amanda's and Meredith's DNA mixed on spot that reacts to luminol in someone else's room? How many odds do you think you have?
I don't know, why don't you tell us? What
are the odds of finding the DNA of those two housemates mixed on a spot that reacts to luminol in someone else's room, if police have been walking around in the murder room and in Filomena's room, assuming that Amanda was not involved in the murder?
You keep acting as if finding Amanda's DNA in the house where Amanda lives proves something.
We also know that Meredith's DNA did not show up in some traces that were visible and were blood for sure. And we know that DNA test may be not that sensitive and subject to deterioration when exposed for long to bacteria and agents (we are talking about samples collected several weeks later). This is expecially true if DNA is from white cell nucleus (very fragile) instead of epithelial cells. We also know that there were blood traces that showed only Amanda's DNA, primarily the blood drop on the faucet. This is highly significant, even if it is not Meredith's DNA. Bear in mind that I'm looking for evidence of Amanda's presence on the scene of murder, not specifically for Meredith's DNA.
Arguing that the test is unreliable is worthless as a strategy, if your goal is to get to proof beyond reasonable doubt that Amanda murdered Meredith. All you can do with that strategy is to argue that we can't prove conclusively that Amanda
didn't do it based on the DNA test results.
The real problem is that we have computer evidence now to support Amanda's alibi, and DNA evidence doesn't come with a time stamp. If Amanda was not there when the murder happened, then she didn't do it. If Amanda didn't do it then any DNA traces found around the house must have been there before the murder, which is perfectly possible. So almost no DNA result is going to overrule the alibi evidence in a rational person's mind.