If one reads the Mudcat FAQs, one would find the following:

I've said it before, and I'm sure I'll say it many times more: the best way to deal with both flamers and trolls is to ignore them. Give them silence, and they'll go away. They feed on attention - don't give it to them.

There is another problem that occasionally arises here - people who are threatening in their behavior. It is of utmost importance that you do not try to deal with these people. If you ignore them totally and inform Joe Offer or Pene Azul about them quietly with a personal message or e-mail, we can quietly make them disappear (to an extent).
PLEASE DO NOT TRY TO DEAL WITH THESE PEOPLE YOURSELVES.
If people seem dangerous, LEAVE THEM ALONE.