The US Defense Department has spent more than a year testing a device obtained through an undercover operation that some investigators believe may be connected to the mysterious illnesses known as Havana Syndrome, according to four sources briefed on the matter.
The device was purchased by Homeland Security Investigations (HSI), a division of the Department of Homeland Security, in the final days of the Biden administration, using funds provided by the Pentagon, two of the sources said. Officials paid an amount in the “eight figures” for the device, though they declined to provide a more precise figure.
The device remains under examination, and its potential link to the dozens of anomalous health incidents that remain officially unexplained is still a matter of debate. Some officials continue to express skepticism that it is connected to the illnesses.
The device acquired by HSI produces pulsed radio waves, one of the sources said — a mechanism that some government officials and academics have speculated for years could be responsible for the incidents. While the device is not entirely Russian in origin, it does contain Russian components, the source added.
Officials have long struggled to understand how a device powerful enough to cause the types of injuries reported by some victims could also be made portable. That question remains unresolved. One person briefed on the device said it is small enough to fit inside a backpack.
The acquisition has reignited a deeply divisive and painful debate within the US government over Havana Syndrome, officially referred to as “anomalous health episodes.”
The illness first came to public attention in late 2016, when US diplomats stationed in Havana began reporting symptoms resembling traumatic brain injuries, including severe headaches, dizziness and vertigo. In the years that followed, similar cases were reported among US diplomats, intelligence officers and military personnel in locations around the world.
For nearly a decade, the intelligence community and the Defense Department have sought to determine whether those officials were targeted by a directed-energy weapon wielded by a foreign government. Senior intelligence officials have repeatedly stated publicly that there is insufficient evidence to support that conclusion, while victims argue that key evidence pointing to Russian involvement has been ignored.
Despite the uncertainty, defense officials considered the findings significant enough to brief the House and Senate Intelligence Committees late last year, including details about the device and the testing underway.
One growing concern among officials is that if the technology proves viable, it may have spread beyond a single actor. Several sources warned that more than one country could now possess a device capable of inflicting serious, potentially career-ending injuries on US personnel.
It remains unclear where or from whom HSI acquired the device. However, HSI has a long history of collaboration with the Defense Department on operations conducted worldwide. The agency has broad authority to investigate crimes related to customs violations, including cases involving the illegal transfer or proliferation of US-controlled technology or expertise.
These investigations are considered one of the most significant points of collaboration between HSI and the US military, according to a former Homeland Security official.
The official said that when US military forces discovered American technology in places such as Afghanistan or Iraq and questioned how it arrived there, HSI would often be brought in to investigate.
It is also unclear how the US government first learned of the device’s existence. Havana Syndrome and its origins have remained frustratingly opaque to both intelligence analysts and medical experts.
One major challenge for the medical community has been the lack of a clear definition of what constitutes an anomalous health incident. In many cases, medical testing was conducted long after symptoms began, complicating efforts to determine what physical damage may have occurred.
In 2022, an intelligence panel concluded that some cases could “plausibly” have been caused by pulsed electromagnetic energy emitted by an external source. However, in 2023, the intelligence community stated publicly that it could not link any of the incidents to a foreign adversary, deeming it unlikely that the illness resulted from a coordinated attack by an enemy of the United States.
As recently as January 2025, the broader intelligence assessment maintained that foreign involvement was very unlikely, though officials emphasized that the possibility could not be entirely ruled out in a small number of cases.
That stance has angered many victims, some of whom believe that intelligence evidence clearly shows Russia was responsible for their injuries. Several have suffered symptoms severe enough to end their careers. Some current and former intelligence officers have also raised concerns that investigations into the incidents were minimized or softened.
For some victims, the discovery and testing of the device represents potential vindication.
“If the US government has indeed uncovered such devices, then the intelligence agencies owe all the victims a major and public apology for how we have been treated as pariahs,” said Marc Polymeropoulos, a former intelligence officer who has said he was injured in an attack in Moscow in 2017.
