>> reporter: yeah, jake, basically we're learning some very new information about what aaron alexis was doing in the hours before he allegedly came on to the navy yard and started shooting. exactly one day before that, he came right here to the sharpshooters gun shop in lorton, virginia, a suburb of washington, d.c. he was here a few hours and basically what he did was, he paid the store to use one of their rifles. he also bought some ammunition for that rifle and he stayed here at the gun shop, at the target range. he did some target practice with that rifle and then he bought a remington 870 12 gauge shotgun. we're also told he bought about two cases of ammunition, about 24 shells, with that. now, while he was here, they ran his name through the federal background check database. it took a couple hours. he was here a couple hours. but basically, there was no problem in that background check. he had a valid out of state