(concurring).
Although I am in agreement with most of the well-reasoned opinion and with the ultimate conclusion of Judge Adams, I am persuaded that the government’s amendment of the conspiracy indictment constitutes an additional ground for reversal. It is elemental that defendants *1277in a federal court must be tried on the specific charge brought by the grand jury. The grand jury in this case named as co-conspirators De Cavalcante, Vastóla, and Annun2Úata, and “other persons whose names are to the Grand Jury unknown.” Brennan and Dello Russo were summoned and appeared before the grand jury. They were persons whose names were to the grand jury known, not unknown. The theory of the government’s case at trial was predicated on the active participation of these two men as leading actors in star roles, not as supporting characters in the conspiracy. Without proving their active participation, the government could not have assembled the bare bones of a conspiracy.
Because Brennan and Dello Russo were known to the grand jury, they would have been named as co-conspirators by that body if the conspiracy was of the type pressed by the government at trial. Therefore, the conspiracy theory presented by the government could not have been that outlined by the grand jury when it returned the charge.