The Defense Department has spent more than a year testing a device purchased in a covert operation that some investigators believe may be the cause of a series of mysterious illnesses afflicting US spies, diplomats and troops known colloquially as Havana Syndrome, according to four sources briefed on the matter.
A division of the Department of Homeland Security, Homeland Security Investigations, bought the device for millions of dollars in the waning days of the Biden administration, using funds provided by the Department of Defense, according to two of the sources. Officials paid “eight figures” for the device, these people said, declining to offer a more specific number.
The device is still being studied and there is ongoing debate – and in some quarters of the government, skepticism – about its connection to the dozens of anomalous health incidents that are still officially unexplained.
CNN has reached out to the Pentagon, HSI and DHS for comment. The CIA declined to comment.
The device acquired by HSI produces pulsed radio waves, one of the sources said, which some officials and academics have speculated for years could be the cause of the accidents. Although the device is not entirely Russian in origin, it contains Russian components, this person added.
Officials have long struggled to understand how a device powerful enough to cause the kind of damage some victims have reported could become portable; which remains a key question, according to one of the sources informed about the device. The device can fit in a backpack, this person said.
The acquisition of the device has rekindled a painful and contentious debate within the US government about the Havana Syndrome, officially known as “episodes of anomalous health.”
The mysterious illness first emerged in late 2016, when a group of US diplomats stationed in the Cuban capital of Havana began reporting symptoms consistent with head trauma, including vertigo and extreme headaches. In the following years, there were cases reported around the world.
In the subsequent decade the intelligence community and the Department of Defense have tried to figure out whether those officials were the victims of some kind of direct energy attack by a foreign government — with senior intelligence officials saying publicly that there was insufficient evidence to support that conclusion and the victims arguing that the US government mixed them up and ignored important evidence that Russia was attacking US government officials.
Still, defense officials considered their findings serious enough that they briefed the House and Senate Intelligence Committees late last year, including a reference to the acquired device and its testing.
A major concern now for some officials is that if the technology is viable it could have proliferated, several of the sources said, meaning more than one country could now have access to a device that could be capable of causing career-ending injuries to US officials.
CNN could not learn where – or from whom – HSI bought the device, but HSI has a history of collaboration with the Department of Defense for operations that take place all over the world. The office has broad jurisdiction to investigate crimes related to customs violations, including investigations into the proliferation of US-controlled technology or expertise abroad.
Those investigations are “the single largest point of collaboration between HSI and the US military,” according to a former Homeland Security official.
For example, when the U.S. military finds U.S. technology in Afghanistan or Iraq that raises questions about how those components arrived in the region, it turns to HSI, according to the official.
It was also not clear how the US government found out about the existence of the device in order to buy it. Havana Syndrome – and its cause – have remained frustratingly opaque to both the intelligence community and the medical community.
One problem facing the medical community is that there is still no clear definition of “abnormal health incidents” or AHIs. The tests were done, in some cases, long after the symptoms started, making it more difficult to understand what happened physically.
In 2022, an intelligence panel investigating the cause of AHIs said that some of the episodes could “plausibly” have been caused by “pulsed electromagnetic energy” emitted from an external source.
But in 2023, the intelligence community said publicly that it could not link any case to a foreign adversary, and decided that it was unlikely that the unexplained illness was the result of a targeted campaign by an enemy of the United States. As recently as January 2025, the broader assessment of the intelligence community remained that it was highly unlikely that the symptoms were caused by a foreign actor – even as an official with the Office of the Director of National Intelligence emphasized that analysts cannot “rule out” the possibility in a small number of cases.
That position has long incensed the victims, many of whom firmly believe that intelligence exists that offers black-and-white evidence that Russia is behind their symptoms, some of which were severe enough to force withdrawal.
Some current and former CIA officials have raised concerns that the agency leaked its investigation, CNN previously reported.
The acquisition of the device was treated by some victims as potential vindication.
“If the [US government] indeed uncovered such devices, then the CIA should give all the victims a major ap**king and a public apology for how we were treated as pariahs,” Marc Polymeropoulos, one of the first CIA officers to go public with injuries he said he sustained in an attack in Moscow in 2017, said in a statement to CNN.
CNN’s Kylie Atwood contributed to this story.
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