He is a timewaster/fantasist. Just block

The amount of people who are apparently police, want to waste time texting and never book is unbelievable. If he carries on texting, just ask him to give you a call when he wants a booking and leave it at that.

Timewaster and/or fantastist, who doesn't realise that while your job is legal, him impersonating a police officer is not!

I feel he is a TW and has no intention of booking as any police officer knows that you are doing nothing illegal. My reply would probably be that it is good he has a working knowledge of the law so he knows that I am doing nothing illegal and that should make him more comfortable in a booking that I am sure he will be making in his next message.
Then if he messages again just send a reply that sounds like a auto-reply something like "please ring me to arrange a booking I do not take bookings unless I have spoken to you" or "in your message please make sure you have given me the date, time, duration and location for any meet as I only reply to messages with those details"
I would not meet this guy but if he has messaged you on AW the site does expect you to reply or the client can report you which is a pain

Local pimp playing with you 

Interesting reply comments here and mine is simple.

Block and ignore.  I have never had a potential client state his profession in an initial message and not even on a phone call. It may happen during the booking and that's fine. Some men have a fantasy of being in uniform and it can be police, army, fireman etc. They think it impresses us. Not me.

Yes asking why he mentions being in the police may produce an interesting response but even so I would refuse the booking (which was probably never genuine anyway).

Ignore and save number as a time waster. Also never bother replying to txts that just say ‘hi’ and little else or something similar. Genuine clients will at least open with a sentence ‘hi interested in booking today’ at the very least.

This. He would have lost me at "Hi"