This episode's headline: Striking Back; LAPD Blues; Welcome?; Conversation. The guests include WILLIAM WILLIAMS, Police Chief; ANDREA ORDIN, Christopher Commission; JOHN MACK, Urban League; DR. RICHARD KLAUSNER, Director, National Cancer Institute; CORRESPONDENTS: PETER MORGAN; JAMES MATES;. Byline: In New York: ROBERT MAC NEIL; In Washington: ELIZABETH FARNSWORTH