There are plenty of ways to investigate group organized terror, either cellular or memetic or ideologically based.

Average number of people killed in sprees when the police are the “first responder”: 18

Average number of people killed in sprees when an armed local citizen is the “first responder”: 2

I don’t know if that’s true, or even accurate, but it does seem likely to be. I’d love to see an actual paper, with a data trail, that shows what the real numbers are.

I agree: in a situation like this, the only response that matters, really, must be very quick. That’s why someone armed at the scene is probably the only way to prevent a lot of carnage.

Of course, without the police’s arrival, even after that much time, the shooter probably would have been able to kill even more people. In the Breivik shooting, the perpetrator reportedly had an hour and a half to do his damage before police arrived (it was on an island). He stalked and killed 77 people.

“One gets on the screen he’s literally suppressing a smile”

When I was a teenager, I attended a citizenship seminar that included visits from state politicians and a couple naturalized citizens on what America meant. One was a woman whose family had survived Nazis and had fallen asleep in a ditch when they were discovered by Russian soldiers who raped her mother and sister, then shot them all. She SMILED the whole time she told this part of the story, a terrible smile that was sort of pasted-on.

I didn’t see that sort of smile again until I attended the funeral of a close family friend’s who was brutally killed. And we laughed so much at the wake that the funeral director had to come in and quiet us down. We were in shock and clutching at straws.

Also, people on the autistic spectrum tend to have inappropriate reactions to emotional situations. Smiling at a loved one’s death was mentioned in a textbook I read last year; I think it was called “Look at me when I’m talking to you” or something like that.

Incidentally, a few years ago here in the Detroit area, there was a woman killed in the parking lot of a grocery store. When he talked to the reporters, he didn’t display the “proper” amount of grief, so people started suggesting that he had a hand in killing her. It turned out that no, he didn’t. It was a complete stranger who was jacking her car who killed her. The family even had a press conference to discuss what it was like to have people turning on their dad, who was basically just an undemonstrative guy.

In general, government conspiracy theories are more popular with the right, and corporate conspiracy theories are more popular with the left.