Me too. Welcome back btw.
It was handled so unprofessionally that the mind boggles. Not one, but many factors surrounding the find of the silencer should have rendered it an unsafe piece of evidence, yet it was a corner stone in the whole case against JB.
The only way to undermine the moderator evidence would have been to establish a reasonably likelihood the blood got there as a result of natural contamination- which there is no natural way for wet blood to be sprayed inside so that it is deposited on the first 8 baffles- or evidence to establish a reasonable likelihood the blood was planted.
The defense lacked the ability to establish any reasonable prospect either happened and thus went with a Hail Mary play hoping that enough jurors would be willing to believe it was June and Nevill's blood mixed and that Sheila had put the moderator away after she killed everyone with it.
They got the prosecution expert to admit it is a remote possibility he was wrong and that it was Nevill and June's blood mixed. So they had evidence to make the claim it was their blood mixed though the evidence failed to amount to a reasonable possibility.
They had no evidence at all to support any other natural way for the blood to have gotten there than drawback. There isn't even a remote possibility for it to have gotten there naturally by some other operation it is impossible.
While it theoretically is possible for blood o get there by intentional planting there was no evidence to establish even a remote chance of that having occurred. Plenty of evidence existes to refute such a notion while not exists to support it having happened.
The defense chose not to make the allegation it was planted since they had nothing to support the allegation and went with the admission it was drawback but argued it was June and Nevill's blood.
On appeal they can raise the claim that the evidence was planted only if they can produce evidence to establish a reasonable likelihood it was planted. All their efforts to find evidence of planting failed. They found no such evidence. So they were unable to make the claim and making the claim without evidence would be futile anyway.
So on appeal they stuck with the same argument and claimed the DNA results prove the blood in the moderator was June and Nevill's blood though the DNA results proved no such thing.
They need evidence that Sheila's blood was in the rifle and not in the moderator. That is what is needed to undermine the moderator evidence which in turn would result in the conviction being overturned. They need to prove her blood was in the rifle itself not in the moderator. The blood removed from the moderator was destroyed by testing and whatever wasn't destroyed by the testing itself was not retained. So there is nothing to scientifically test to prove the blood removed from the moderator wasn't Sheila's. Similarly there is no scientific test that could prove they removed Sheila's blood from the rifle and concealed the finding. Only someone's admission that they found her blood in the rifle and concealed such finding could help to establish such and that would require the claim being credible with the person having opportunity to do such motive etc.
Similarly only a credible admission of planting evidence in the moderator could help establish such occurred. No scientific testing can accomplish this only testimonial admissions. Realists would face these facts.