Umm, I hate to break it to you jpmills, but if girt is a cheater, than so are you. You admit in your original post (assuming 100% accuracy for arguments sake) that another coach sent you a sitemail saying we both have A+ prestiges, let's not fight over a player and instead use our A+ prestiges to beat out other schools. You then dropped off of the referenced recruit and went out and got a different one. As collusion requires 2 people, you and girt worked together to collude against other coaches. Again, assuming your post is true.
Now, considering your entire evidence in this allegation amounts to "i'm telling the truth cause girt is a cheater" and he has denied the facts of your original post, I hope there is more evidence other than "they write the same style". If not, simple answer to all problems, if someone sitemails you for info, delete it, then its a waste of their time.