Of all evil I deem you capable: Therefore I want good from you. Verily, I have often laughed at the weaklings who thought themselves good because they had no claws.
The prosecution wants to make sure the process by which the evidence was obtained is not truthfully presented, because, as often as not, that process will raise questions.
But like infection is the petty thought: it creeps and hides, and wants to be nowhere--until the whole body is decayed and withered by the petty infection... Thus spoke Zarathustra.