Whoever did this may have been trained in Afghanistan, but is not necessarily Afghan.
Plus, there is lots of information out there on how to make IEDs.
I wonder if these were typical WalMart cookers or if they were imported?
If you were Achmed Fookin Mohamtard, would you fly to the U.S. luggin two pressure cookers from Achmed's (not the same Achmed) Kitchen Wares, or you just pick up a couple at WalMart?
Ever notice that Usama's followers were silent when he was killed. Cuz....he was retired and useless!!! That fort was their idea of Senior Housing.