These guys were basically unemployed drifters, except that they had guns, a car, a GPS, etc.
Also, there are reports that Muhammed was traveling extensively recently.
Somebody was paying the bills.
If it is established, don't expect a PEEP out about it by the main media, or Pacific Radio, etc. They will continue to focus on the idiotic aspect they are hyping of "Gulf War Veterans Turned Hard Core Killers Back Home".