Mob Witnesses to Testify Behind Screens

Some federal officials being called as witnesses at the Chicago trial of a deputy U.S. marshal charged with leaking secrets of a major mob investigation will be allowed to testify behind screens so spectators won't see their faces.

The witnesses are expected to testify at the trial of John T. Ambrose, who's charged with whispering the secrets concerning the government's landmark Operation Family Secrets investigation to organized crime.

The witnesses are officials of the government's ultra-secret witness security program (WITSEC). They'll also use bogus names to keep their identities secret.

The trial is due to get under way Monday.