U.S. Loses Murder Case Over Lying Witnesses
Brooklyn Federal Judge John Gleeson overturns murder conviction of Angel M DeAngelo, saying prosecutors relied on 'blatant, critical perjury' by witnesses; stops short of saying prosecutors knew their witnesses were lying at jury trial in April, but expresses distress over actions of US Atty Roslynn R Mauskopf and says he fears innocent man was convicted; decision is second in recent months in which federal judge found that prosecutors in Mauskopf's office relied on false information; photo (M)