WASHINGTON — U.S. intelligence officials are closely studying Cold War-era Soviet technology as they seek to determine whether an electronic weapon was used to disorient and injure 24 American officials in Cuba earlier this year.

Two intelligence officials tell POLITICO they’re confident that the attacks were conducted with an “energy directed” or "acoustic" device, possibly similar to one used by Soviet intelligence in Havana more than four decades ago, but remain unsure of its exact nature.


That has officials combing classified files and even contacting retired intelligence officers for clues to a mystery that has triggered a diplomatic crisis less than three years after President Barack Obama restored diplomatic relations with Havana.

“We’re trying to talk to guys as far back as the 1960s,” said one of the intelligence officials.

The sweeping, governmentwide search for answers — spearheaded publicly by the State Department — has pulled in expertise from intelligence agencies, science and weapons development offices and health officials. Still, answers remain elusive. “It’s baffled the entire community,” the intelligence official said.

While investigators remain unsure of who, exactly, was behind the apparent attacks, one former U.S. intelligence official says their leading theory holds that it was the work of Cuban intelligence — possibly even a rogue faction of Cuban spies hoping to derail the restored diplomatic ties between Havana and Washington. Moscow is another prime suspect, though U.S. officials are undecided whether the Russians might be the main aggressors or accomplices, or absent altogether.

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The attacks against U.S. officials — including CIA officers — in Cuba began shortly after Election Day in fall 2016, and continued periodically until at least August 2017. Affected personnel reported hearing high-pitched sounds and exhibited symptoms reflective of a concussion, including dizziness, nausea and memory issues.

Of particular interest to federal officials is the former Soviet technique of using radio waves, like microwaves, to target U.S. signals collection in Moscow. In the 1970s, amid escalating spy tensions between the United States and Russia, the Soviets targeted the U.S. embassy in Moscow with radio microwaves in an effort to disrupt U.S. radio surveillance of Russian interests in post Cold-War Moscow, according to multiple Cold War-era recountings. The incident, known as the “Moscow Signal,” was never formally solved — after the U.S. embassy installed screens in its compound, the issue went away.

The use of energy waves or sound as weapons can be a particularly nasty form of covert attack. Not always audible to the human ear, the mysterious devices have surfaced in rumors periodically in Cold War spy history. Answers have remained as ambiguous. As far back as the 1970s Moscow Signal incident, medical professionals suspected the use of such mysterious weapons could lead to brain damage, blood disorders and hearing impairments in exposed personnel — symptoms nearly identical to what targeted U.S. officials are experiencing now.

But intelligence officials are split on what might have motivated the use of an energy device now: Was it meant to harm U.S. diplomats — or could the injuries be an unintended side effect of a surveillance operation?

The affected U.S. officials were targeted at their homes and in hotels, one of the intelligence officials said, leading some to conclude that the attacks were intended to harm, not surveil, U.S. personnel. Tracking when and where U.S. personnel were staying in hotels suggests a more narrow, intentional targeting, the official said.

At least five Cuba-based Canadian officials have experienced similar symptoms — some of them during vacation stretches on the island, according to two of the intelligence officials, further raising suspicion that the presumed attacks were not related to surveillance.

The affected Havana-based U.S. diplomats are still undergoing medical observation and treatment.

The restoration of diplomatic relations with Havana was one of President Barack Obama’s proudest foreign policy achievements. But the end of nearly six decades of animosity was not universally celebrated: Many Cuban government hard-liners still harbor festering anti-Americanism.

If the attacks are indeed the work of a renegade Cuban intelligence faction, the former U.S. intelligence official said, that might be a sign that Cuban President Raúl Castro’s grip on power — he succeeded his brother, Fidel, as president in 2008 — may not be as strong as many outsiders assume.

But while the intelligence community is primarily focused on the role of Cuban intelligence, officials are closely examining the possibility that a third-party — likely Russia — is involved, in part because of strong denials by Castro.

“The Cuban government has no responsibility whatsoever in these incidents which are said to have affected the U.S. diplomats,” Cuban Minister of Foreign Affairs Bruno Rodriguez Parrilla said at the Washington National Press Club in early November.

Just as some Cuban hard-liners opposed Obama’s diplomatic overture, their longtime allies in Moscow feared that a Cuban-U.S. rapprochement might jeopardize their intelligence presence on an island less than 100 miles from the U.S. mainland.

Of the nearly half-dozen current and former U.S. officials with whom POLITICO spoke, none even entertained that Moscow — a longtime ally and patron of the Cuban intelligence services — was not somehow involved, or at least aware of the attacks.

“They’re trained by the SVR. They’re dirtier than the SVR,” one recently departed counterintelligence official said, referring to Moscow’s foreign intelligence service. “It would surprise me greatly if the Russians didn’t know about it.”

Even as U.S.-Cuban relations have thawed in recent years, Russia has stayed close to its historic ally. Just before a January 2015 visit by a U.S. congressional delegation, Moscow docked a high-tech spy ship in Havana. More recently, the Kremlin reportedly reached an agreement with Havana to reopen its sweeping Lourdes signals collection base near that city.

The lack of answers is starting to rankle U.S. policymakers. House Foreign Affairs Committee chairman Ed Royce (R-Calif.) wrote to the State Department on Monday, asking for more details on State’s investigation into the incident and the status of the affected diplomats.

“While many Members hold different views on U.S. policy towards Cuba, we all agree that the health and safety of our diplomats and their families is vital to the national security of the United States,” the letter said.

The letter asked whether the State Department has “new evidence or analysis to suggest the source of these attacks,” asking whether “at least some element of the Cuban government has knowledge of the source of these attacks.”

For now, the answer to that question remains a mystery.

Nahal Toosi contributed to this report.

CORRECTION: An earlier version of this story inaccurately stated where Soviet intelligence operatives had used radio microwaves to target US officials in the 1970s. The microwaves were used against U.S. assets in Russia, not Cuba.