You would think that
1- After many years of schooling to be alert and good at diagnosis, psychiatrists could pick up on dangerous conditions.
2- After months/weeks of therapy with a qualified psychiatrist, whatever the perp’s condition was that led to the murder spree, would be successfully treated and thereby lessen his murderous urge.
This was not a crime of passion, this was a very pre-meditated murder spree.
Its sad to think that if there are no clear determinants, of very harmful individuals, we’re all in danger.