“ After the receipt of this message, a New Orleans FBI agent telephoned the Associated Press, the local newspapers and a local television channel and inquired whether they intended to cover the arrival of a 'prominent person' at the airport that evening. [2] When the Delta plane arrived, the press swarmed around Marcello. With them were FBI agent Collins, who according to the Government's brief and the Court of Appeals was 'posing as a passenger,' and FBI agent Avignone, carrying a camera. ”