It was a hot, humid evening, a night for frayed nerves and flaring tempers. Answering a call to Manhattan's Lower East Side, where a man had been reported roaming the streets with a rifle, a pair of New York cops last week began questioning a teen-age tough—and found themselves threatened by riot. A hostile crowd of some 200 persons milled around, a shower of bricks and other debris hurtled down from tenement rooftops. One brick, aimed at the policemen, struck and killed a bystander, Factory Worker Ramon Rojas.
That incident, for which two teen-age youths were arrested, was not isolated:...