Michael Anthony Brewton stepped off the bus last night within a block from where his son was fatally stabbed two days before, only to stumble onto the aftermath of another violent crime. A few minutes before Brewton got off the bus in downtown Richmond, a 19-year-old man was punched and robbed shortly before 7 p.m. outside the old Central National Bank building at 219 E. Broad St. on the south side of Broad, police said.