Comments and email addresses

I’m having a little trouble with spammers posting spam on the existing posts and not leaving an email address. I want this so that I can post the spammer on the StopForumSpam site.

Is there a plugin that will force people who comment on an existing post to provide a valid email or be rejected? The spam is being caught by Askimet so there’s no chance of it getting through and I have to approve all comments anyway.

I have looked through the plugins but can’t spot anything that will fit the bill.

My current settings are as follows and I can’t figure out how they are managing to post. I’ve looked at my userlist and nothing stands out. Also the spam comes from different countries.

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