There is no crime in the email exchange you describe. Were you to consummate the deal, and actually meet this person, it is entirely possible you could be charged with patronizing a prostitute if it is alleged that money was exchanged for proposed sexual conduct (see PL Section 130 for definition). Such a scenario could occur if it turns out the person you think you are dealing with is an undercover cop. You are playing with fire here.
I agree with Mr. Keller's wise response. I too see no crime and I'm curious what makes you think the matter would have come to law enforcement's attention. Please leave me guessing. Do not post anymore details; you've put too much out there already.