Scientists say microwave signals may have caused brain injuries to 33 US officials and their family members at embassies in Cuba and China.
The saga began in 2016 when 24 US diplomats and their family members fell ill after being exposed to what US officials claim was some form of "sonic attack".
The victims suffered permanent hearing loss, severe headaches, loss of balance, brain swelling, and disruption to cognitive functions.
Many victims claimed to hear strange noises before the symptoms appeared. One diplomat reported a "blaring, grinding noise" that woke him from his bed in a Havana hotel; others say they heard "loud ringing or high-pitch chirping".
Some said they could walk "in and out" of areas where the noises were blaring.
Then in May this year, at least nine Americans associated with the US consulate in Guangzhou were medically evacuated after workers complained of strange aural sensations.
At least one government employee in Guangzhou was confirmed to have developed a brain injury consistent with that of the 24 US diplomats and their family members who fell ill in Cuba.
Symptoms of the mystery illness include dizziness, headaches, tinnitus, cognitive issues, and difficulty sleeping, the US Embassy said.
The office of US Secretary of State Mike Pompeo responded by establishing a task force aimed at getting to the bottom of the mystery.
On Saturday, the New York Times reported that doctors and scientists think microwave weapon strikes may be to blame. It's a great story, involving a secret society of scientists and 57-year-old theory about microwaves stumped up by neuroscientist Allan H Frey.
Amazingly, the "Frey effect" is a staple of any conspiracy theorist's daily diet of wackiness. It's behind one type of the alleged "mind control" attacks that requires a tinfoil hat to negate its affects on the brain. They'll call it "V2K" - Voice to Skull.
A look back at Frey's research in 1961 turns up some alarming consistencies with what US embassy staff reported in Cuba and China. He exposed subjects to pulsed microwave radiation, from various distances up to hundreds of feet away.
At higher peak power densities, the induced sounds were described as "a buzz, clicking, hiss, or knocking".
Further alterations enabled Frey to induce the "perception of severe buffeting of the head, without such apparent vestibular symptoms as dizziness or nausea".
Various detractors through the years since then have broadly asserted such a thing couldn't be weaponised against humans, due to such things as the enormous heat effect it would have to create, and high radiation levels.
But we know for certain that at least one US company has claimed to have created such a weapon in the past decade.
The people from Jason are here to see you
The New York Times reports the investigation has been handled by "members of Jason, a secretive group of elite scientists that helps the federal government assess new threats to national security".
"The microwave idea teems with unanswered questions," it reports.
"Who fired the beams? The Russian government? The Cuban government? A rogue Cuban faction sympathetic to Moscow? And, if so, where did the attackers get the unconventional arms?"
The FBI has declined to comment, of course.
But they have definitely followed the Frey effect line. The NYT knows because Allan H Frey is still alive, and they visited him. Frey, 83, said federal investigators "have questioned him on the diplomatic riddle and microwave radiation is considered a possible cause".
Sitting at his kitchen table, Frey was even happy to give the NYT his theory that "Cubans aligned with Russia, the nation's longtime ally, might have launched microwave strikes in attempts to undermine developing ties between Cuba and the United States".
If you really want to know what it can sound like, here:
And all those years ago, Frey also found that you don't need a full tinfoil hat to protect yourself - just a patch of wire mesh placed above the temporal lobe (just above and forward of the ears).
All the State Department would tell the New York Times was that "its investigation hadn't yet determined the attacks' cause or source".
This article was originally published by Business Insider.
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