What I should have said was that if current laws had been enforced the shooter would not have been able to purchase the gun legally.
Of course he could have made an illegal purchase.
My point was that the gun laws proposed would have had no effect on the shooter.
They would have stopped the neighbor from being able to prevent more killing. The gun laws proposed would have prevented the neighbor from owning a gun.
They would have caused more people to be killed.
Absolutely spot-on.