I don't get how it's important that he got the gun in a legal fashion.
The true problem should be that due to the legal structures, it's very easy to get a gun (if lying on a dead-giveaway question like that isn't even checked).
Shakran: After reading up on the second amendment and its history, I can't say I agree with you on your interpretation of that sentence.
Due to the brevity and unclear (to me) phrasing, it had me going around a bit, but
"A well regulated militia, being necessary for the preservation of a free state, the right of the people to keep and bear arms shall not be infringed"
http://en.wikipedia.org/wiki/Militia
"Militia is the activity of one or more citizens organized to provide defense or paramilitary service, or those engaged in such activity. ........ a militia is distinct from a regular army"
So interpretation of the word Militia alone, can even make a huge difference as to the exact meaning of the amendment.
Given that alot of people seem to interpret it very broadly anybody, even on their own, can qualify as a militia at some point.
It sounds like the constitution defines a militia as being necessary for a free state to function, and because of this, the right of people to bear and keep arms will not be restricted within limits:
Infringe
In the context of the Constitution, phrases like "shall not be infringed," "shall make no law," and "shall not be violated" sound pretty unbendable, but the Supreme Court has ruled that some laws can, in fact, encroach on these phrases. For example, though there is freedom of speech, you cannot slander someone; though you can own a pistol, you cannot own a nuclear weapon.
http://www.usconstitution.net/glossary.html#INFRINGE
I can't say I agree with the 2nd Amendment, *at all*. But that to me is what is written in your (America's) constitution.
edit: cuz I forgot to add the bit about interpretation of Militia halfway in my post.