So what would you have had them do? He had committed no crimes up to that point, and suddenly withdrew from the university after failing his oral exam, which was probably the final mental trigger for his rampage.
They were obviously concerned about him, and no, you don’t actually have to have killed somebody to be considered a threat.
A mentally ill person who is fantasizing about killing people is a threat, and should be committed for observation and stabilization for at least 30 days. The “72 hour committment,” which is the max in most places, is not enough.
Virtually all of our recent mass murderers, including the Columbine duo, had been expressing threats and their parents had tried unsuccessfully to get them committed to residential care.
There was no argument over the fact that Holmes was mentally ill, and the school owed it both to him and to the general population that he was targeting to make sure that he received treatment or was kept in a situation where he would not present a threat until such time as he could be stabilized.
He probably failed the oral because his life was going out of control, btw, not the reverse; and in any case, if that was the final “trigger,” then he should have been prevented from being in a situation where it could happen. And that means supervised residential treatment.
I have had two friends who were unable to get long-term residential treatment for their manic-depressive young adult sons - and both of these young men killed themselves (one of them by causing an automobile accident that almost killed someone else) after being released from 72-hour observation with a handful of drugs because the system could not hold them any longer.
The whole failure here is that of the university. Universities always hide what they consider their dirty laundry, whether it’s a mentally ill student or a child-molesting football coach.