How to catch a "dirty cop"

If you were going to set up operations to catch crooked cops what would you do? Or perhaps as importantly, what wouldn't you do? Here in NSW they're about to start "cleaning out the pockets of police corruption" (I just love what The Daily Telegraph does with headlines!). We know this, from the Telegraph piece which also reports that suspect officers will be set up in targeted sting operations. Is that the smartest thing to publicize? Or is it a clever ploy? By making it public that you are going to target officers perhaps all of them will start doing the ''right thing".