My hope is that they used a prepaid THINKING it is untraceable. Not many things are truly untraceable! In Beverly Carter's case, slick Arron bought a burner phone to use for the interaction. But, all things can be traced where they came from (Dollar General, in that case). Then, they went to Dollar General and got the video footage of the purchase. Even when the product isn't directly connected to the person, through some good detective work, it can be linked. (I think it was that case! So many cases, so little brain space)/
I def don't think this was a robbery. A robber comes in quickly searching and grabbing and stuffing stuff they want in their pants or whatever. This person didn't steal anything but weapons! Were the weapons placed there by them earlier to come back and use? Its probable. And when someone comes in on a robbery, the robber generally runs for the hills! They don't stick around, bludgeon someone in the head and still leave without anything of value. Doesn't at all seem like a robbery gig, to me. Seems very targeted. Seems very calculated. Seemed very at peace with this mission they were on. VERY scary, to me.