One, if you're uncomfortable with a photographer, you shouldn't be doing a shoot — period.
Two, you should really be bringing an escort to your female photographers anyhow, especially if you go on location; what makes you think she isn't the 'front' and there isn't a load of thugs hiding in the back room.
Three, you should always do your homework, talk with with references, and make sure the photographer can be located. A photographer that hides their contact information isn't one you should be dealing with. Check references.