From the article it mentioned that the gunman, posed as policeman, asked people to gather around before shooting. Those victims were taken by surprise.

Well, if you look at the handy sidebar in the article... looks like he at least has the record for the last 15 years.

And for something slightly more constructive, it appears like the gunman is this guy:

http://www.torontosun.com/2011/07/22/olso-attacks-suspect-pr...

(I know its the Sun.. but the name checks out with other sources)

Looking at past incidents, the early reports have almost always turned out to be wrong, even though they often become the basis for the commonly held perception in the publics eye.

For instance, there was no child molestation at Waco, yet people think there was. (nor were they suicidal. Koresh, when he heard the ATF was asking about him in town, called up the local ATF office and asked to set up a meeting so he could answer any questions they had. Yet, the media reports that he was "hiding out" necessitating the "raid" on the "compound".) I picked waco as an example because it is long enough ago that maybe it can be considered objectively.

The day of the incident is when spin is the most effective. Getting out the "official story", even if it turns out to be absurd or outright false in retrospect, is paramount. It doesn't matter when the truth comes out-- most people will never hear it, and many who do won't believe it because the person spreading it, no matter how much evidence they have, is going against the "official story" and therefore is a "conspiracy theorist" and thus has no credibility.

This is how the public is manipulated into believing disprovable things.