In November 2016, American diplomats in Cuba complained of persistent, high-pitched sounds followed by a range of symptoms, including headaches, nausea and hearing loss.

Exams of nearly two dozen of them eventually revealed signs of concussions or other brain injuries, and speculation about the cause turned to weapons that blast sound or microwaves. Amid an international uproar, a recording of the sinister droning was widely circulated in the news media.

On Friday, two scientists presented evidence that those sounds were not so mysterious after all. They were made by crickets, the researchers concluded.

That’s not to say that the diplomats weren’t attacked, the scientists added — only that the recording is not of a sonic weapon, as had been suggested.