It's nearly a month later. Why wouldn't you have dumped it?
Maybe you could get by 48 hours or so after stealing it, but not later, I wouldn't think.
Oh yeah focus on the military...
I'm saying it's possible that these two guys sold the cards after killing the women from whom they stole the cards. They may have even recently sold the card(s) on the black market. The card(s) would have been left active, to assist the police in Alabam in solving the case. Therefore, they could have proven to a buyer that the cards were still good.