I heard it was because the Dutch wont allow armed air marshals on flights that take off from the Netherlands. Not sure it that is true.
doing a little more research:
ticket bought at KLM office in Accra on December 16
he would have had to leave on a Wednesday to get a Friday arrival date on NWA..the one way ticket I am finding has a 26 hour layover.
The 26 hour layover was apparently to give him time find his contact in Amsterdam and get his panties on.