(Gresham, OR)  --  Gresham police are warning residents about a man posing as a utility worker in an effort to enter people's homes.  Authorities say the incidents have happened in locations that include the intersection of Northwest Division Street and Mawrcrest Drive, and an apartment complex in the 27-hundred block of West Powell Boulevard.  Police say a man, wearing no uniform or badge, knocked on doors claiming to work for a utility company and asked if he could come in and check the residents' services.  Officials say none of the residents let the man into their homes.