During the night of January 7, 1943 Nikola Tesla died in his room at the Hotel New Yorker. The morning after the inventor's death, his nephew Sava Kosanovic hurried to his uncle's room at the Hotel New Yorker. He was an up-and-coming Yugoslav official with suspected connections to the communist party in his country. By the time he arrived, Tesla's body had already been removed, and Kosanovic´ suspected that someone had already gone through his uncle's effects. Technical papers were missing as well as a black notebook he knew Tesla kept—a notebook with several hundred pages, some of which were marked "Government."
Several trunks of papers, records and equipment were removed from his room by the Department of Justice Alien Property Custodian Office. According to the controversial president of the FBI, J. Edgar Hoover, "they did not have any knowledge of the fact that the papers were photographed or that his men did such thing". The controversy of the "missing papers" begins by the fact that Tesla was already a citizen of the USA and for this reason this is a division of the U.S. government that should not even have authority or jurisdiction over Tesla's estate. According to the FBI, the papers were carefully analyzed by John G. Trump, a RADAR scientist at MIT, along with several high level Naval Intelligence officials. Trump declares that the papers do not contain any new information which would “constitute a hazard in unfriendly hands” and the papers are deemed safe to be released. Trump includes an analysis of Tesla’s particle beam papers in his report, concluding that the plans do not contain enough information to actually build a weapon and that any workable configuration would be of very limited power. Anyway today these papers are supposed to be in the Nikola Tesla Museum in Belgrade, Yugoslavia.
According to the official statement by the FBI:
When Tesla died in New York in January 1943, his papers—which were thought to include plans for a particle beam weapon, dubbed a “death ray” by the press—were temporarily seized by the Department of Justice Alien Property Custodian Office (“alien” in this case means “foreigner,” although Tesla was a U.S. citizen). Despite longstanding reports and rumors, the FBI was not involved in searching Tesla’s effects, and it never had possession of his papers or any microfilm that may have been made of those papers. Since 1943, we have told a consistent story to all who have asked. Reports to the contrary appear to be based on an initial confusion of FBI agents with other government officials—especially Alien Property Office personnel. These rumors have long been repeated in biographies and articles on Tesla without double-checking the facts as reported in our files.
Articles in Tesla's hotel room after his death. Note cabinets and one of the invertor's safes. Three packages of Nabisco crackers can be seen on one of the upper shelves of the cabinet at left.
File is made available free to download under the Freedom of Information Act request on February, 2013 by the FBI: