The FBI Files

The declassified files are real, extensive — and far more mundane than the legend. Here is what is actually in them.

The seizure

Tesla died on 7 January 1943. Two days later, representatives of the Office of Alien Property — the wartime agency that took custody of property belonging to foreign nationals — entered his rooms at the Hotel New Yorker and seized his effects: papers, notebooks, and apparatus. The government’s interest was straightforward and, in wartime, reasonable: Tesla had spent the 1930s announcing a “death beam” in the press, his nephew Sava Kosanovic was a Yugoslav official with suspected communist ties, and nobody wanted a weapons design falling into Axis hands — or Soviet ones.

The Trump review

The government needed an engineer who could tell a death ray from a doorbell. It called in Dr. John G. Trump, an MIT electrical engineer working with the National Defense Research Committee. Trump examined Tesla’s papers in OAP custody on 26–27 January 1943 and reported back within days. His conclusion, on the record:

Tesla’s thoughts and efforts during at least the past 15 years were primarily of a speculative, philosophical, and somewhat 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.

The miscellaneous apparatus found in Tesla’s rooms, Trump reported, was not prototype weaponry but archaic electrical instruments. The government’s own expert found nothing of military value — and said so in writing.

What’s actually in the file

The FBI’s declassified Tesla file (file no. 100-223235) runs to roughly 250–300 pages, released in parts through Freedom of Information Act requests — the FBI posted the main file to its public Vault, and an additional 64 pages of previously processed material were released in 2018. Its contents:

• Correspondence about the seizure — memos between the FBI, the Office of Alien Property, and the Justice Department over who had Tesla’s effects and what to do with them.
• The Trump report — the engineer’s written conclusion, quoted above.
• Tips and crank letters — members of the public writing in with claims about Tesla’s inventions, alleged death-ray devices, and demands that the papers be released. The file documents the claims, not their truth.
• Surveillance-adjacent paper — interest in Kosanovic’s movements and in who might seek the papers, reflecting wartime counterintelligence routine rather than a cover-up.
• Decades of follow-up letters — well into the Cold War, citizens wrote to J. Edgar Hoover demanding Tesla’s papers be made public; the Bureau answered, repeatedly, that it did not hold them.

What the files don’t contain

They do not contain a working death-ray design. They do not contain evidence of a suppressed superweapon. They do not show the FBI keeping Tesla’s “most dangerous inventions” — the effects were the Office of Alien Property’s, and they eventually passed to Kosanovic and then to the Nikola Tesla Museum in Belgrade (established 1952), where researchers can study them today. The lore inverts the file: the documents record a government looking for a weapon and failing to find one.

The honest bottom line

The FBI files are a case study in how legend outruns paper. Everything sensational about them — the seizure, the secret review, the missing notebook — is real. Everything conspiratorial — the hidden death ray, the buried breakthroughs — is absent from the very documents the conspiracies cite. Read the file, not the YouTube description of the file.

Source notes

• Seizure (January 1943), OAP custody, Kosanovic, wartime rationale: contemporary press (January 1943); Seifer (1996).
• Trump examination (26–27 January 1943) and the quoted conclusion: Trump’s report as reproduced in the declassified FBI file.
• File number (100-223235), page count (~250–300 pages), FBI Vault release, and the 2018 release of 64 additional pages: FBI Vault records and contemporary press coverage (e.g., MuckRock, March 2018).
• File contents (correspondence, Trump report, tips, Kosanovic material, decades of public letters): the declassified file itself.
• Transfer of effects to Belgrade and the Tesla Museum (1952): the standard biographical account.
• The “what the files don’t contain” verdict: the file’s own contents; presented as the record’s verdict, not as proof of a negative.