Would it not be a good time to have a serious discussion on a national ballistic fingerprinting program -- "the keeping of an electronic record of the markings that the weapons leave on the bullets or shell casings" -- right now?
It can be well argued that "If we had that fingerprinting [for rifles], that guy wouldn't be free right now."
Ballistic fingerprinting would be able to prevent some future attacks of this nature. The events in Maryland and Virginia have made arguments against it shallow.