possibly, you'd have to ask an admin / owner about it.
You could (possibly) locate him through an ip, to his isp, through logs and user database and find records on him, but that's iffy. You couldn't do it yourself, an ISP isn't going to disclose information to a random person, maybe if the police / investigation person asked them they would give it to them.
as i said the forums aren't responsible for these transactions. you are.