(Portland, OR)  --  Police are following up on a report of a man who exposed himself to a ten-year-old girl while she walked home from school in North Portland.  Authorities say the man was riding a bicycle when he approached the girl Tuesday afternoon and began to ask her questions before he exposed himself.  Police say the incident happened in the area of North Denver Avenue and Bryant Street.  The suspect is described as a white man in his 30s, with a medium to thin build, brown hair and mustache, wearing a blue t-shirt, blue cap, shorts, and black sneakers.