Gun control in the US will lower the number of spree killings, but crime of other types will rise, as existing career criminals (who won't turn in their guns) will be emboldened to attack, knowing the average citizen & small business will not have guns to defend themselves.

This also wasn't a spree killing. It was a targeted murder of 2 people. If this guy couldn't have obtained a gun, he could have killed at least one of the victims, perhaps both, with a different weapon.