Another Paper Leaked on Tiananmen; Killings Still Gnaw at China's Leaders
Another secret document from violent crushing of pro-democracy demonstrations in 1989 is smuggled out of China, one of several recent signs that deadly crackdown around Tiananmen Square continues to haunt Communist Party and its top leaders; document was written from prison in September 1989 by Bao Tong, top party official who was jailed for sympathizing with student demonstrators; was his official response to charges against him and includes new details of high-level decisions in frenetic weeks before Army shot its way into Tiananmen Square on June 4, killing hundreds and leaving unresolved national trauma; Bao, former adviser and speechwriter for Communist Party chief Zhao Ziyang, was held in solitary confinement for seven years on charges of leaking state secrets; currently lives in Beijing under house arrest (M)