As long as there is insistence that this is a new trial, with only one piece of evidence, it will be difficult to understand the case. If the knife is perceived as the most important piece of evidence, and that only the recent test is relevant, the evidence will be difficult to understand.
In Canada, it is possible for a prosecutor to appeal a decision. In Canada, there is no difficulty in understanding the difference between a trial, and an appeal of a verdict. In Italy, the prosecutor appealed a verdict and we are now hearing the appeal arguments in the appeal. This is not a new trial, this one speck of DNA on the handle on the knife is not the only evidence and there is, to date, no reason to conclude that the knife is the most important piece of evidence. This piece of DNA hidden in the handle of the knife is evidence that was misinterpreted by the last team of experts, so it has been retested as part of the process of ensuring that all the facts are correct.