When I look at the idea of gun control (which is an extremely general phrase), I don't see it helping prevent incidents such as this.
Perhaps my idea as to what “gun control” constitutes is different from yours, but I cannot see how more restrictions on who buys guns, what they must go through to get them, how much ammo they can buy, what types of guns they can purchase, what features those guns can have, etc., etc., would in any way have prevented this incident.
Someone owned and (apparently) legally purchased those weapons, this mad/insane person had access to them, and he used them to kill people for some reason I’m not sure anyone will ever know.
So what would stop that?
You keep screaming (or so I interpret your prolific use of the capslock key) that we need to look a gun control, but what do you mean when you say that?