Federal prosecutors, who launched their case last week, contend that the Avenues gang between 1994 and 2000 conspired to kill African Americans on their turf. Men, women and children were harassed, terrorized, assaulted and slain as gang members sought to force black residents out of Latino neighborhoods, prosecutors said. Authorities are using a federal hate-crime law based on the amendment to the U.S. Constitution that outlawed slavery, and another law created in the civil rights era, to go after four gang members. Barbara Bernstein, deputy chief of the criminal section of the civil rights divisions of the U.S. Department of...