This might help a little, but, like all things in the Internet spamming world, there are ways around anything. There is a program called Visualware in which you can type in the IP address and it will show you the route it took and the final destination of where it came from, if it is really the true IP address. I have this program at home and I know the DOD uses it.
Just go to google, type in Visualware and read up on it and see if it is what you are looking for. You might be able to block the IP range if that helps. Other than blocking the IP range, I am not sure they is much more than you can do because they can always spoof their IP address into another range which is just as frustrating or find another ISP and continue their game.
Unfortunately, this type of thing is common and is very frustrating to those in the security field because for every one that is taken down, three more pop up within a few hours.
I know it is not the answer you really wanted to hear, but this is just the tip of the iceberg. Good luck.