dont really know but I sometimes would check the number online on yellowpages.com to see where the # is from. You can only see the location of the # but not who it is issued to, you have to pay extra

Probably not much help.  The reverse directories generally just use the listings in white/yellow pages.  No cellphones, unlisted numbers, or recently  
activated or transfered numbers.  

Finally, PBXs can be programmed to push out any number they want.  Certainly would be the thing to do for undercover police work.

Get the TER VIP and enter the number into the review search.  See if she has reviews...  once again, a well reviewed lady (several reviews by reviewers who have done a few) most likely is both NOT LE & also delivers as agreed.  (There is never a guarentee of chemistry but at least the other basics are covered.)  
skb