People in this country have no idea how much power prosecutors have. It's insane, and almost without oversight. And as in this case, many places have the institutional incentive for their entire criminal justice system to close ranks. Oftentimes, this is justified; after all, prosecutors will have always have difficult, legitimate cases and need all the help they can get. But, like the Blue Wall of Silence, this comes very close to misconduct and certainly becomes a tragedy in cases like this.
Also, this Onion story is terrifyingly spot-on, especially the ending: