re: #536 A Mom Anon

Spree killers can and do go on shooting rampages without being mentally ill; they will do so out of having an agenda or for revenge or other reasons.

A couple that come to mind:
Major Nidal Hassan.
Anders Breivik (his mental status is currently being debated by the Norwegian courts)
The Columbine massacre shooters.

Shooting rampager with mental health concerns:
The VA Tech shooter.

It’s not nearly clear cut as you say.