Police officer Wenjian Liu was buried in Brooklyn Sunday, ending at least one chapter in the citywide ordeal that began Dec. 20 when he and officer Rafael Ramos were murdered as they sat in a patrol car. On Saturday, local residents gathered in Chinatown for a smaller remembrance. City Council member Margaret Chin helped organize a vigil in Chatham Square for those who couldn’t attend the Brooklyn wake and funeral. Quite a few people braved the rain and cold to say a prayer for Liu and to light candles in his memory. His burial was delayed to give family members time to travel from China.