The shooting that occurred on July 20, 2012 in Aurora Colorado could have been prevented if the significance of seemingly isolated prior events were recognized and integrated into a whole picture beforehand.
Firstly, from a general description of the shooter as a shy, introverted loner it could have been conjectured that there was a possibility that he was some type of schizophrenic character. Secondly, from the fact that shortly after starting graduate school he dropped out for no apparent reason, it could have been surmised that he was undergoing a psychotic breakdown at that time. Although these observations were presumptive evidence that the individual was having a psychotic break, they gave no indication that he was homicidal. However, a third observation made by his neighbors was a strong indication that he actually was potentially a homicidal paranoid schizophrenic: Shortly before the shooting, he covered the windows of his apartment with newspapers. To a trained psychiatrist, the emotional significance of this act was a telltale sign that he was in a state of acute psychotic panic and that, as a result, he was suffering from persecutory delusions. From his perspective, he was in mortal danger for at least two months prior to the shootings and this is why he had to arm himself to the hilt offensively and defensively in every way possible in order to protect himself from harm. From this perspective, it was irrelevant whether he bought a thousand rounds or ten thousand of ammunition. By playing the Joker, the murders were a psychotic attempt to defend himself from his inner terror by projecting the source of the danger to his life onto the outside world.
If the emotional significance of his suddenly covering the windows was correctly understood by those around him as a bizarrely psychotic act, it could have been possible to prevent this and other similar tragic events from happening. (Remember that the Oslo mass murderer also covered his windows just prior to the killings.) It is possible with knowledge that is currently available to educate the public to be aware of the behavioral signs and symptoms in people that lead them to commit homicidal acts.