WASHINGTON – Massive protests against police brutality nationwide capped a week that began in chaos but ended with largely peaceful expressions that organizers hope will sustain their movement.Tens of thousands of people marched Saturday with few reports of problems in scenes that were more often festive than tense.Wearing masks and urging fundamental change, protesters gathered in dozens of places from coast to coast while mourners in North Carolina waited for hours to glimpse the golden coffin carrying the body of native son George Floyd, the black man whose death at the hands of Minneapolis police has galvanized the expanding movement.Collectively, it was perhaps the largest one-day mobilization since Floyd died May 25 and came as many.