That is the biblical adage of "an eye for an eye and a tooth for a tooth". If you look very closely into the background of this, one of the express conditions for this applying is that you lied to get someone else punished. You then faced the exact same punishment.

So for law enforcement, any lies or withholding of evidence to ensure conviction would automatically mean that the penalty being asked for is applied to all of those law enforcement and prosecutors involved. There would be no "free passes" given to law enforcement or prosecutors.

This, of course, will not happen any time soon in most jurisdictions.