Caught a league hacker, question.

We have an exact IP match (and confession) from someone who has been hacking league members on an interleague ladder (for pool), and I was wondering if there was anything that could be done on a larger scale than just waiting to see if he ever re-joins the ladder and banning him on just the one ladder. He also hinted at hacking names of another, separate ladder as well. Who would I contact about this, specifically?