not for long.
Agreed. If it turns out that the guns were purchased by a green card holder, I predict a revision in federal law removing this privilege in the near future.
Also, in response to another poster, it is quite possible that if this perp had a Green Card, and had only been in the USA since August, that he was issued the Green Card OVERSEAS at one of our US Embassies/Consulates, after a long period of processing, so it does not necessarily follow that the Green Card he may have had was "fake".