Another incident of fake money being used at a Ridgefield store is under investigation.  Ridgefield Police say a local business received a counterfeit $20 on Tuesday night.  Police say it appears that the bill came from a store in Norwalk.  In late June, Ridgefield Police arrested a New York resident on a Forgery charge for passing counterfeit bills.  In that case, a Brooklyn teen was charged for allegedly trying to use a bogus $20 bill at a gas station on Danbury Road.  At that time Ridgefield Police cautioned businesses to use tools at their disposal to determine whether cash is legitimate.