This is another setup of:

Create a solution

Cause a problem

Fix problem with your solution

In this instance, because the owner of the gun had a license (despite being Australian), he had legal access to his gun (Class A) and now the Prime Minister wants to change the law to ahem outlaw semi-automatic rifles.

Ringing bells?

https://www.stuff.co.nz/national/111322923/prime-minister-says-nz-gun-laws-will-change-in-wake-of-christchurch-terror-attack