Relax folks.
I think you might have taken Kontrolor's comments a bit on the personal side, which is obviously understandable. I had the privilege to listen to someone who knew Peter Nielsen express his view on single man operations... very emotional and yet straight to the point.
I think Kontrolor just said that Peter Nielsen was the last barrier of defense (or perhaps the last slice of swiss cheese) and as such, he also failed. Emphasis is on "also", there were lots of other failures to actually allow him to be in that situation.
Back on the original topic, I obviously do share the necessity for justice in Peter Nielsen's murder. It was a horrible thing done to somebody innocent who was not to blame for the accident. However, to be true to justice I would need to ask myself if the murderer was really in a state of mind in which he could really know good from bad.
There is a reason most democracies don't put on trial underage criminals, even murderers, or if they do it's with a very light sentencing. Minors are not expected to be able to know the consecuences of their action and neither are those mentally ill. I think the trial took into consideration that the obsessively grieving father and husband was mentally impaired at the time of the murder.
To lock him up for the next 40 years will not bring Peter Nielsen back... I'd prefer a bit of mercy and forgiveness, the murderer has already the worst sentence nobody could wish for him.