Expelled student armed with assault rifle slaughters 17 at Florida high school

[Catfish]

Very sad. I do not know "where this will stop", but it is obviously happening more and more often.
They say "It is the person that kills, not the weapon." Hm, sure. But making it more difficult to get those guns could be a start?

(OT i read that inspite of Trump whos is pro-gun and NRA, there are less people buying weapons now.. which was explained because Trump is less likely to take guns away from them, so there is less need for defense. An american thing.)
How do you "test" people whether they are prone to do such things, without taking away the freedom of, and for all?

From my german point of view the case is clear, but it is seen entirely different over there.