The "signs" are always "obvious" in retrospect - it's the predicting what human beings will do in the murky future that's tough.
Even if required reports are made to authorities - they're not always legally actionable at that point. I recieved a ominously threatening letter once, and it was reported. But there were no specifics, guy said when questioned (I assume, not like the police gave me a transcript) that he was just pissed off, and didn't mean it that way. Nothing further happened (to him, or anyone else). But, let's say he HAD gone on to commit some violent crimes - every single reporting rule had been followed and the police had followed up to the best of their ability.
(There seems to be an implication that generally people at that university would hold a gun range owner in some kind of disdain. I'm not sure where the data for that came from, or what the relevance to the discussion or chain of events would be...)
It now seems the person he sent his notebook outlining his intended killings was also his on campus psychiatrist.
Whom he had been seeing professionally for a few months at least.
I am wondering why several PHD's and at least one psychiatrist didn't notice he was heading around the twist and got him more or better help, or at least alert the administration of their suspicions.
One gun clinging, undereducated(at least not to their standards), normal guy who owned a gun range noticed and was concerned. And seemed on the verge of calling the authorities on him.
Um. So, there is no education or profession that makes somebody a mind reader or fortune teller. There's a number of odd ducks running around this world, inside and outside of academic institutions. It's not a crime to have other people think you're "off", nor do most of these people commit crimes. What I find astonishing is the number of people who actually DO tell their physicians, psychologists, and psychiatrists about violent thoughts of harm or self-harm. If they don't bring it up, or deny it when questioned, and their behavior doesn't demonstrate otherwise - guess what? Free country. (Yes, right now every body is looking back and saying "of course he was headed for this! I thought so at the time!" The retrospectoscope is the only instrument with supposedly perfect visualization...)
Alert administration of their suspicions (if they truly had any at the time, and he didn't just seem like a duck too odd to function in their department)? There are some huge legally privacy issues there. Since (correct me if I'm wrong) the psychiatrist is employed by the university, both HIPAA and FERPA might apply. And all administration can do is either take action such as forcing a medical withdrawl from the university (and he withdrew on his own), or call the cops. Who need something fairly specific to go on. Call them and they may go talk to him - but unless he gives them some further cause to act (like making stupid threatening statements or demonstrating that he has committed some crime) the police can't just arrest him because he made his psychiatrist or his department head really worried.
As far as I can tell, the timeline on which he sent the notebooks to his psychiatrist, when they were recieved, and the details that might be in them, are disputed, and I'd wait on the actual court proceedings to see what really happened there (there's gag orders on everybody in this, so we're not going to get hard info pretrial, I think.)
"When someone shows you who they are believe them" M. Angelou