(Portland, OR)  --  Police are looking for a suspect in an armed robbery in North Portland.  Investigators say a man and a woman were walking early yesterday morning in the area of North Mason Avenue and North Mississippi Street, when they were accosted by a man who displayed a gun and demanded all their belongings.  The man, who wore a bandanna over his face, is described as African-American, about six-feet-two, between 30 and 40 years old.  Anyone with information is asked to call Portland Police.