Here is the thing:  I can perfectly well understand that you wish to keep things private but your employer now knows that something is up as he or she has been contacted by the police.  Once charges are filed and you are arrested the matter will become public record and then you will have no control over the situation.  It may be better for you to go and present the matter to you employer in the best light it can be by explaining what happened and your side of the story.  The arrest record and/or indictment will not be the facts most favorable to you.  And you are wrong that a criminal charge has nothing to do with your jib.  Employers want employees that they can trust and depend on an that will not bring bad press to their company.  So think about the situation as a whole and get yourself a lawyer.