Caporegime
I'm being flippant. The point is he wasn't supposed to have the guns, so it's ok that he killed people with them because he was already off the map. You don't need any more laws. You can just say that someone didn't obey the existing laws at some point. Everything is fine, ignore it, look the other way, wait for the next one.Doesn't sound like the system was working - there were all sorts of reasons that in pretty much any other country would have precluded him from being able to own a gun and should have meant he couldn't buy a gun - but he was able to purchase them anyhow due to a mixture of poor organisation and omitting details.