Couple chapters...Double Cross & American Gestapo from Mark Riebling's work 'Wedge From P.Harbor to 9/11 How the Secret War Between the FBI & CIA has Endangered National Security'..

... AGENT TRICYCLE HAD SPENT December 7, 1941, getting a suntan. To arrange for receipt of a radio transmitter, he had left New York City by Pan Am Clipper on November 14, making Rio de Janeiro by the 18th, and giving the torn half of his business card to “Alfredo, ” the Abwehr’s top agent in Latin America. Alfredo had agreed to send a transmitter to Quebec, where Popov could pick it up. Popov was returning to America aboard the luxury cruiser S.S. Uruguay, which was just pulling out of Port of Spain, Trinidad, when the captain told the passengers about Pearl Harbor. Popov would recall feeling a pulse of pride. Despite his problems with the Bureau, he knew that American officials had possessed his Pearl Harbor questionnaire since August 19, which was almost five months’ warning. He was confident, he later said, that the United States had scored a great victory—and bitter when he learned the truth.

As Popov arrived at Manhattan on December 15, 1941, FBI agents were ferried out in a tugboat and boarded the ship before it entered the harbor. Popov would record that he grilled the agents about their failure to use his Pearl Harbor intelligence; Bureau records have been censored on “national-security” grounds exactly at the point where such recriminations should have been documented. But when Popov told the agents that his Brazilian handler had given him more microdot queries, the Bureau’s reaction was plainly more electric than it had been in August, before America was at war. “This is vitally important, ” Hoover scrawled on the case summary. “Get copy of ‘dots’ so I may see them.” By year’s end, the FBI was finally playing Tricycle as a double agent, using him to disinform the Germans—an undertaking crucial to any eventual U.S. invasion of the Continent. But the Bureau’s approach to this deception game would only further alienate Popov and his British sponsors, causing a dramatic expansion of Donovan’s empire.

Popov told the agents that the new dots were concealed in “butterfly trays”—souvenir serving platters with beautiful dead specimens preserved under clear enamel. Like most of the returning tourists on the Uruguay, Popov had brought home a few of the trays, and immediately after the boat docked, agents seized all of them on board.
https://exploringrealhistory.blogspot.com/2020/04/part-2-wedge-from-pharbor-to-911-how.html