We all agree that if assessed as a threat, potential or actual, the threat must be "neutralised". I think, just to isolate them in prisons or "ghetto enclaves" is not the answer. Our prisons were not designed for this type of criminal, and the ghetto would just be a festering pit of growing discontent storing up more trouble for the future. Perhaps some kind of "corrction centres", whatever the cost!! This could involve a full range re- direction, through to lobotomy if required. Maybe they could be sent to an ISIS war zone of their choice as an alternative.
Sounds a bit George Orwell, but needs must and all that.