The 9-year-old girl's mother was gone only briefly Monday, running upstairs to the 11th floor to borrow a hair-straightening comb to help give the girl braids before a barbecue downstairs in the courtyard. The girl was playing with one of her closest friends, with whom she spent so much time that some thought they were related, an 11-year-old named Queen Washington. Everyone called her Queenie. In the 9-year-old's apartment on the seventh floor of the Linden Houses in East New York, Brooklyn, the two girls began to fight over a ball, the police said. As any parent will tell, even...