Why is it that always an innocent person is hanged instead of the culprit?

like the recent aero show 2011 bribery case, I am not at all able to find any article or any news about the IAF officer who had asked bribe but instead I am finding that the person who had blown the whistle against the officer ( according to TOI 23/3/2011 ) is being black listed . now you tell me is this justice or injustice? don't you think every individual has democratic right to fight or to speak?