This should be ROUTINE practice in police investigations, to guard against corruption of witness testimony, but, alas, we all know counterexamples. Moreover, it is a professional ethics violation for prosecutors to make excessively detailed statements to the press (who are always willing to ask for as many details as they can get) about the course of an investigation in progress and about possible motives for a crime when the accused has not yet been put on trial. The principle of "innocent until proven guilty" is STILL important, despite many cases we can observe where it appears to be violated.
The human mind leaps to supposing explanations and forming a narrative around new, disturbing events. The mind is a "belief engine"
http://www.amazon.com/The-Believing-Brain-Conspiracies-How-C...
and all of us would like to get an answer, even a quick and dirty answer that may be flat wrong, rather than have unanswered questions about a shocking news story. I remember well the speculation that swirled around the Columbine High School shootings some years ago. I was active in a different online community then, and a bunch of programmers were unembarrassed about going beyond the limits of their occupational knowledge to endorse various hypotheses about why the shooters killed their classmates. Right now we don't know why James Eagan Holmes shot movie-goers, evidently planning well in advance to kill many strangers. I'm not going to speculate about it.
The public-health perspective on violence reduction is interesting, because it doesn't depend on knowing much about the motives of individuals. The theory is that certain risk-reduction measures work in general, minimizing the chance that some individual will engage in any kind of incident like the one in Aurora, Colorado. Gun control is such a sensitive issue in the United States that it is barely being discussed yet by politicians in connection with the incident this weekend, but differing national patterns of gun control have been mentioned by commentators who point to the example of Australia's response to the 1996 Port Arthur, Tasmania shooting
http://edition.cnn.com/2012/07/20/opinion/donohue-gun-contro...
http://news.ninemsn.com.au/national/8502957/smaller-risk-of-...
as the right way to reduce risk of further mass shooting incidents. That's food for thought. So far I am not aware of any reason for young people in residential neighborhoods in the United States to have what are called "assault rifles" for legitimate purposes, and I certainly would be glad to know that none are in my (crime-free) neighborhood.
First edit: I see other Hacker News commenters are picking up on the submitted article's author's remarks on depression. This may be overgeneralizing too much from one example, even though the author also refers to a Secret Service study of the small number of examples of school shooters studied to that time. I think the author's most accurate point on that issue is "A vast majority of depressives are a danger only to themselves."