Well it's just you seem to believe there there is only one or two corrupt people in previous MOJ's.
Why dont you start by studying Drake's MOJ's and Vanezis' MOJ. Seems a good starting point. Come back and tell us how many people were involved.
In Court and at trial is very different what you imagine Roch, i think the gathering of evidence and availability of evidence has tightened up to what it used to be and there is more pressure on the police when questioning. In Court, being a defendant or Victim your at the hands of the Judge and Barristers, it's the way it is and the way it will always be i'm afraid. Things get held back from the Jury during discussion between the Prosecution and defence, everything doesn't get brought up at trial.