Did Russia chase the US diplomatic mission out of Cuba — and try to do the same thing in China? According to NBC, US intel agencies believe they know who’s behind a series of bizarre and mysterious illnesses that befell diplomatic personnel in Havana starting two years ago, and which suddenly started appearing in China this year. And they’re pointing the finger at Moscow, although they don’t know yet exactly how it was done:

An @NBCNews exclusive: After more than a year of mystery, Russia is the main suspect in the sonic attacks that sickened 26 U.S. diplomats and intelligence officials in Cuba. @MitchellReports has the latest. pic.twitter.com/NEI9PJ9CpD

— TODAY (@TODAYshow) September 11, 2018

Intelligence agencies investigating mysterious “attacks” that led to brain injuries in U.S. personnel in Cuba and China consider Russia to be the main suspect, three U.S. officials and two others briefed on the investigation tell NBC News.

The suspicion that Russia is likely behind the alleged attacks is backed up by evidence from communications intercepts, known in the spy world as signals intelligence, amassed during a lengthy and ongoing investigation involving the FBI, the CIA and other U.S. agencies. The officials declined to elaborate on the nature of the intelligence.

The evidence is not yet conclusive enough, however, for the U.S. to formally assign blame to Moscow for incidents that started in late 2016 and have continued in 2018, causing a major rupture in U.S.-Cuba relations.

A couple of years ago, the possibility of Russia being behind the attacks may not have made much sense. After the brazen and obvious assassination attempt on Sergei Srkipal with the Soviet-produced Novichok, it seems anything’s possible:

If Russia did use a futuristic weapon to damage the brains of U.S. personnel, it would mark a stunning escalation in Russian aggression toward Western nations, compounded recently by the use of a military-grade nerve agent to poison an ex-spy and his daughter in Britain. Although the full extent of the resulting diplomatic fallout is difficult to predict, a determination that Russia was behind the Cuba attacks would trigger outrage in Congress and foreign capitals and calls for an immediate, concerted response, especially as President Donald Trump faces continued questions about his willingness to challenge Russia and President Vladimir Putin.

Actually, Trump has shown himself willing to act against Putin, even while his rhetoric remains more accommodating. Trump ordered the expulsion of scores of Russian diplomats and the closure of multiple diplomatic properties in response to the Skripal attack, for instance, as well as adding on significant sanctions against Russia and individual Russians. That was for an attack on the UK, too. If American intel agencies can demonstrate that the sonic attacks came from Russia, not only would Trump need to escalate that, he has built credit with the UK and other nations to demand that they follow suit as well.

NBC’s reporters write that “the precise motive remains unclear,” but it’s not all that tough to suss out. The US opening to Cuba represented a threat to Russia’s position on the island, at least theoretically, and certainly more so when Barack Obama was president when these attacks began. Deploying whatever weapon caused this would be seen as a Cuban threat, or at least a failure by Cuba to protect foreign diplomats, and would lead to a rift between the two countries. That would leave the field in Cuba to Russia’s large intelligence operation aimed at the US, without American counterintelligence around to oppose and hinder them.

Only a few countries other than Russia would have enough concern over increasing American influence in Cuba and the resources to create and sustain those attacks. China might be another, and Iran as well, but neither have the kind of historical attachment to the Castros that Russia has. Furthermore, the use of the same attacks in China would make Beijing look less likely as a suspect. Russia would benefit from a US-China diplomatic decline too.

Still, the brutality and ruthlessness of such a strategy seems almost out of place in this era — or would, if we hadn’t already seen the Skripal hit attempt and a string of murders associated with Vladimir Putin. Assuming that US intelligence has this right, it’s is yet another reminder that the former KGB colonel has not changed his stripes, and that Russian imperialism existed long before the Soviets, and continues on live on after them too. Perhaps the biggest lesson is that this era isn’t very different from those which preceded it.