Nikola Tesla’s Papers: The 1943 Seizure and the Myth That Followed

On the morning of January 8, 1943, a hotel maid at the New Yorker Hotel in Manhattan ignored the “Do Not Disturb” sign on the door of Room 3327 and found Nikola Tesla dead. He was eighty-six, alone, and almost out of money. The New York City medical examiner ruled the cause as coronary thrombosis. Within hours, agents of the United States Office of Alien Property Custodian were at the hotel. Within forty-eight hours, the papers in his room had been impounded and trucked to a federal warehouse, and an MIT engineer named John G. Trump — the uncle of a future US president — was sitting in front of them with instructions to determine whether the dead inventor had left a weapon.

What Trump actually found, what was actually in those trunks, and where Tesla’s papers actually ended up are some of the best-documented facts in twentieth-century American science history. They are also among the most-mythologised. This is the documentary record, separated from the folklore.

The Tesla the Folklore Skips Over

Before the “lost secrets” story, there is a real Tesla, and most of his most important work was published, patented, and built. He was born on July 10, 1856, in Smiljan, then in the Austrian Empire and now in Croatia. He emigrated to the United States in 1884, worked briefly and unhappily for Thomas Edison in New York, and in 1888 sold his polyphase alternating-current motor and power-distribution patents to George Westinghouse for what eventually amounted to about $200,000 in 1890s dollars — millions in today’s money. Tesla’s polyphase AC system was used in the world’s first major hydroelectric station at Niagara Falls in 1895 and remains the basis of the global electrical grid today.

This is the part of Tesla’s career that is best understood — and most consequential. The “War of Currents” against Edison’s direct current was a real commercial battle, and Tesla won it through Westinghouse. The AC induction motor, the Tesla coil, the basic principles of radio transmission (for which the US Supreme Court restored several of Tesla’s priority patents over Marconi’s in 1943, after Tesla’s death), early work on remote control and robotics, the rotating magnetic field — all of these are public, documented, and uncontested.

Wardenclyffe and the End of the Funding

The story shifts in 1901. Tesla, by then a celebrity, persuaded the financier J. P. Morgan to invest $150,000 in a wireless transmission station on Long Island, designed by the architect Stanford White and called Wardenclyffe. As pitched to Morgan, the project was straightforward radio: trans-Atlantic messages to England and to ships at sea, competing with Guglielmo Marconi.

What Tesla actually wanted to build was a wireless power transmitter — a 187-foot tower with a 68-foot metal dome, sitting over a deep iron-rod and copper-plate grounding system, that he believed could use the Earth itself as a conductor to broadcast electricity to anywhere on the planet. In December 1901, Marconi successfully transmitted the letter “S” across the Atlantic using equipment far cheaper than Tesla’s. Morgan, asked for additional funds, refused — Tesla was, in effect, asking for funding for a project Morgan had not agreed to invest in. The Wall Street downturn of 1903 and the financial Panic of 1907 closed off other investors.

By 1906 most activity at Wardenclyffe had stopped. Tesla mortgaged the property to cover his hotel bills at the Waldorf-Astoria; by 1915 his debt to the Waldorf’s manager, George Boldt, was around $20,000 and Boldt foreclosed. On July 4, 1917, the Smiley Steel Company began demolishing the tower for scrap. It was finally levelled in September. The scrap was sold for $1,750. Wardenclyffe is now home to the Tesla Science Center, which crowdfunded the purchase of the surviving laboratory building in 2013 through a campaign led by cartoonist Matthew Inman of The Oatmeal; the site was added to the National Register of Historic Places in 2018.

The “Death Ray” Announcement

On Tesla’s seventy-eighth birthday — July 11, 1934 — The New York Times ran a front-page story headlined “Tesla, at 78, Bares New ‘Death-Beam’.” Tesla described a particle-beam weapon, which he called “teleforce,” capable, he said, of destroying aircraft and armies at a distance of hundreds of miles. He attempted to interest the US, British, French, Yugoslav, and Soviet governments. The Soviets paid him $25,000 in 1935 for a partial proposal. No prototype was ever built. No working drawings have ever been found.

By 1943, with the United States at war and Tesla still publicly insisting that his teleforce weapon would change history, the federal government had a genuine, pragmatic reason to want to know what was in his papers. The fear was not unreasonable in the abstract — Tesla had spoken publicly about the weapon as recently as the late 1930s, and he was in correspondence with Soviet officials who had paid for partial details. The fear was, however, entirely about what he might have left behind, not about what he had actually built.

The Office of Alien Property Custodian Moves In

Tesla’s nephew, the Yugoslav diplomat Sava Kosanović, arrived at the New Yorker Hotel on the morning of January 8, 1943, only to find that someone had already been through his uncle’s effects. The “someone” was the Office of Alien Property Custodian, acting under wartime authority that, despite Tesla’s US citizenship, treated his Yugoslav-born identity as sufficient justification. Truckloads of papers, notebooks, and equipment were impounded.

The OAPC asked for a technical evaluation. The man chosen was Dr. John G. Trump, then director of MIT’s High Voltage Research Laboratory, a leading American expert on high-voltage electrical engineering, X-ray technology, and wartime radar research. Trump was 35 years old. He was also, as the world would later learn, the younger brother of Fred Trump and uncle of Donald J. Trump.

Over January 8 and 9, 1943, with follow-up sessions across the following weeks, Trump physically examined the seized material. His official memorandum — declassified by the FBI in 2016 and posted online by MuckRock and the Federation of American Scientists — is short, specific, and devastating to the death-ray myth. Trump reported that Tesla’s writings of the previous fifteen years were “primarily of a speculative, philosophical and promotional character, often concerned with the production and wireless transmission of power, but did not include new sound, workable principles or methods for realizing such results.” Trump did not say Tesla was a fraud; he said the late papers contained no implementable weapon design.

What Happened to the Papers

This is the part of the story most often left out of conspiracy retellings, because it removes the mystery. After Trump’s report, most of the seized material was eventually released. Sava Kosanović, who had become Yugoslav ambassador to the United States, secured the bulk of Tesla’s papers and personal effects, and arranged for them to be shipped to Belgrade in 1952. They became the founding collection of the Nikola Tesla Museum, which opened in Belgrade on December 5, 1952 — the centennial year of Tesla’s birth.

The museum today holds roughly 160,000 original documents, photographs, and pieces of personal correspondence, plus Tesla’s cremated remains in a gold-plated urn. In 2003, UNESCO added the Tesla Papers to its Memory of the World Register, an international cultural-heritage listing. The papers are publicly catalogued. Researchers from around the world apply for access.

In 2016, in response to ongoing FOIA requests, the FBI released approximately 250 additional pages of Tesla-related material from its own files, with a further 64-page batch following in 2018. Among the released material is Trump’s full memorandum and an internal FBI catalogue of the papers themselves. The cumulative documentary record now publicly available about Tesla’s “lost lab” runs to thousands of pages.

Where the Myth Came From

The story that the FBI secretly retained Tesla’s most powerful inventions has a single identifiable source: Prodigal Genius: The Life of Nikola Tesla, the 1944 biography by John Joseph O’Neill, science editor of the New York Herald Tribune. O’Neill, a friendly biographer who had known Tesla personally, included an unsubstantiated claim that the FBI had taken possession of Tesla’s “most dangerous” papers and was hiding them in the national interest.

The claim was wrong on the institution — the papers were held by the OAPC, not the FBI — and unsupported on the substance. But the book sold well and was repeatedly reprinted. By the 1950s, FBI director J. Edgar Hoover was personally answering letters from members of the public who, citing O’Neill, demanded that the Bureau release the suppressed inventions. Hoover replied each time that the Bureau did not have them. The FBI eventually traced the entire claim to O’Neill’s book and decided, in 1953, that it was not worth seeking a correction, because the book had already been out for nearly a decade. The myth simply continued to compound from there.

What Most Accounts Get Wrong

The popular retelling of Tesla’s “lost secrets” usually leans on three claims, each of which collapses under examination. First, that Tesla’s papers were secret and remain so — but most are in a publicly catalogued museum in Belgrade and the rest have been declassified. Second, that Trump’s assessment was a cover-up — but Trump’s career and reputation in postwar high-voltage engineering and radiation therapy are entirely public, and his memorandum is internally consistent with what other Tesla biographers, including Marc Seifer in Wizard: The Life and Times of Nikola Tesla (1996), conclude about the late papers. Third, that Tesla had built or even fully designed a working death ray — but no prototype, no detailed schematic, and no independent witness has ever been produced.

The historically honest picture is more interesting than the conspiracy. Tesla in his late period was a brilliant, isolated, increasingly impractical inventor who oscillated between genuine technical insight (his AC patents, his understanding of resonance and high-frequency current) and visionary speculation that he could not, and did not, reduce to working hardware. The seized papers, when examined, reflected that mixture. Some of his ideas — wireless communication, remote control, particle accelerators — were prescient. Some — wireless transmission of bulk electric power across the planet — remain physically impractical for reasons rooted in basic electromagnetism. None constituted, in 1943, a hidden American superweapon.

Why It Still Matters

The Tesla mythology is durable because it satisfies a particular kind of grievance: the suspicion that the world we have is artificially smaller than the world we could have had, and that someone, somewhere, is responsible for the difference. Tesla, real and imagined, became the patron saint of that suspicion in the second half of the twentieth century, and his name now hangs over electric cars, transformer toys, “free energy” YouTube channels, and the comic-book imagination of every reader who learned about Wardenclyffe before learning about Niagara Falls.

What is lost in that retelling is the actual achievement — that an immigrant from a small village in the Austrian Empire died in poverty in a Manhattan hotel room having, demonstrably, designed the electrical system that runs almost every building on the planet. The real Tesla does not need a hidden lab and a missing death ray. The papers we have are enough.

For more on twentieth-century science folklore, see our piece on the Philadelphia Experiment.

Frequently Asked Questions

When and where did Nikola Tesla die?

Tesla died on January 7, 1943, in Room 3327 of the New Yorker Hotel in Manhattan, at the age of 86. His body was discovered by a hotel maid on the morning of January 8. The New York City medical examiner ruled the cause of death as coronary thrombosis.

Did the FBI seize Tesla’s papers?

The seizure was carried out by the Office of Alien Property Custodian, a wartime federal agency, not the FBI directly. The OAPC took possession of Tesla’s trunks, notebooks, and personal effects within hours of his death, citing wartime national-security concerns despite Tesla’s US citizenship since 1891. The FBI itself never had formal custody of the papers, although it received decades of correspondence from members of the public who, following claims in a 1944 biography, mistakenly believed it did.

Who was John G. Trump and what did he conclude?

John George Trump (1907–1985) was a professor at MIT, director of the institute’s High Voltage Research Laboratory, and a leading American electrical engineer specialising in high-voltage and radiation technology. He was also the uncle of Donald J. Trump. The OAPC asked Trump to evaluate Tesla’s seized papers in January 1943. Trump concluded that Tesla’s work of the previous fifteen years was “primarily of a speculative, philosophical and promotional character” and contained no implementable, weaponisable designs.

Where are Tesla’s papers now?

Most of Tesla’s original papers, notebooks, photographs, and personal effects are held by the Nikola Tesla Museum in Belgrade, Serbia, which opened on December 5, 1952. The collection was added to UNESCO’s Memory of the World Register in 2003. Additional Tesla-related material was declassified by the FBI in 2016 and 2018 under the US Freedom of Information Act.

Did Tesla actually invent a “death ray”?

Tesla publicly described a particle-beam weapon, which he called “teleforce,” in a New York Times interview published on his 78th birthday, July 11, 1934. He attempted to sell the concept to several governments and received a $25,000 advance from the Soviet Union in 1935 for a partial proposal. No working prototype was ever built. No detailed engineering drawings have ever been found among his papers in Belgrade, in the FBI’s released files, or anywhere else. Modern directed-energy and particle-beam weapons research, including the US Strategic Defense Initiative in the 1980s, drew on postwar physics rather than Tesla’s notes.

What was Wardenclyffe Tower?

Wardenclyffe was a 187-foot wireless transmission tower built between 1901 and 1902 on Long Island, New York, designed by architect Stanford White and partly funded by J. P. Morgan ($150,000). Tesla intended it to broadcast both information and electric power around the world using the Earth as a conductor. Morgan refused further funding when Tesla expanded the project beyond the originally agreed radio-telegraphy scope, and Marconi’s cheaper transatlantic radio system in December 1901 ended Wardenclyffe’s commercial case. The tower was abandoned by 1906, demolished for scrap in 1917, and the property foreclosed in 1922. The surviving laboratory building is now the Tesla Science Center at Wardenclyffe.

Sources

1. HISTORY — “The Mystery of Nikola Tesla’s Missing Files”
2. MuckRock — “FBI releases catalog of Nikola Tesla’s writings seized after his death”
3. PBS — “Tesla: Master of Lightning — The Missing Papers”
4. Tesla Science Center at Wardenclyffe — Tesla’s Wireless Power
5. American Physical Society — Wardenclyffe Historic Site
6. Smithsonian Magazine — “The Rise and Fall of Nikola Tesla and His Tower”
7. Marc J. Seifer, Wizard: The Life and Times of Nikola Tesla — Biography of a Genius (Citadel Press, 1996)
8. W. Bernard Carlson, Tesla: Inventor of the Electrical Age (Princeton University Press, 2013)
9. John J. O’Neill, Prodigal Genius: The Life of Nikola Tesla (Ives Washburn, 1944) — the source of the long-running “FBI cover-up” claim, included here as a primary document for the myth rather than a reliable history
10. JPat Brown, B.C.D. Lipton, and Michael Morisy (eds.), Scientists Under Surveillance: The FBI Files (MIT Press, 2019)
11. “Tesla, at 78, Bares New ‘Death-Beam’,” The New York Times, July 11, 1934