Of course, a terrible case always happens, and this is such a tragic case. The natural instinct is to think we need to change the system because of one case. That's really the worst thing you can do. You have to pinpoint what happened, if you can.
These cases, as tragic as they are, are also very rare, which makes them very difficult to predict. The risk assessment said four out of five people with his profile would not reoffend. Well, tragically, it means one likely will offend, so how do we figure out who?