Very unwanted users

Hi, I'd like to know if you could help me for my problems (once more)

On my forum, we had a member who joined and intended on intalling a Trojan horse on our forum and then making our site a zone where all the users would be affected. Luckilly he is an idiot and we were able to ban him in time.
My questions are as follows:
-How can I prevent futur f's from doing it again
-Is there something I can do against this f. I have his e-mail address and I.P number (This isn't only for personal revenge but to prevent him from doing it to others)

Here is his e-mail address, so if other people come accoss it, they know of him: [EDIT Katt] I took note of the address. I deleted it from this post, because it's illegal to show other people's email address in public without their consent. You can give us the address in private.

Hello. I think that you should give us his address IP please. The forumactif support will thus poura to identify it.
Contact me with serials-killers@hotmail.com

sure, I'll send it as soon as Peter or Katt tell me if its OK
(sorry, simple principle to only trust people I know)

Do not worry you I did not say to you to give it to me. I thought of Katt by telling us. lol

Well, what's the person's username?

Its pseudonym is Katt.

Nope, the person who is a danger to forums is [EDIT Katt] I took note of the address. I deleted it from this post, because it's illegal to show other people's email address in public without their consent. You can give us the address in private.
he's the one, Ill post his I.P soon

Hello.

I left a message on the French side, in the foreign staff section, to ask for advice, because I'm far from being an expert in juridical questions... I took note of the e-mail address.

Ok thanks, but understand if I don't care about judicial rights, as far as I'm concerned, he lost them the second he treid to f with me. anyway, thanks alot