Your post is bizarre
According to the latest reports, the perp is a “normal” (?) Dutchman, who was a shooting club member and had licenses for 5 firearms.
Now, whatever the motive for this shooting spree might have been, we’ll probably never know because the authorities are likely to filter any information they release to the public. More so, this incident will give the Dutch government enough ammunition to attack the already stringent firearms legislation and maybe, probably, completely ban citizens from owning anything but a bow and 4 arrows.
These are bizarre times.