In life, Tyshawn Lee was a mischievous fourth grader who loved basketball, Xbox and macaroni and cheese. In death, Tyshawn became a symbol of the cycle of gang retaliation that authorities say drives much of the violence in pockets of Chicago’s South and West sides. Nearly four years after the skinny 9-year-old was lured into a South Side alley and shot execution-style by rivals of his father’s gang, separate Cook County juries last week convicted Corey Morgan and Dwright Doty in his killing. A third defendant, Kevin Edwards, pleaded guilty before the trial. All were allegedly members of the Bang...