(Portland, OR)  --  The Portland Police Bureau says it declared an unlawful assembly Saturday night after dozens of demonstrators gathered to protest the police killing of a man in Lents Park.  Police say about 70 people gathered outside the bureau's east precinct building to protest the officer-involved shooting of 46-year-old Robert Delgado on Friday.  Police say the protesters blocked traffic and pushed a dumpster toward the precinct door in an apparent attempt to block the entrance.  Police shot and killed Delgado while responding to a report that he was carrying a gun.