For months, U.S. officials in Cuba have been investigating what led to a series of attacks against personnel working in the embassy in Havana.
While they haven’t yet determined what’s caused 21 victims to be mysteriously injured, audio recordings obtained by The Associated Press on Thursday shed light into what they may have heard before suffering the effects of the undisclosed attacks.
The recordings feature sounds similar to a group of crickets, but at a much higher pitch. They reportedly started some time after Donald Trump was elected president and have been sent to the U.S. Navy for analysis and to other intelligence services, but they haven’t given investigators much to go on.
Victims of the attacks describe hearing a noise inside and outside their homes and they became ill a short while later. According to an AP story, some of those U.S. workers who have been described as spies suffered the most severe damage, including brain damage and hearing loss.
“The recording gives us the first tangible sense of what it was like for these American government workers in Havana who were hearing these unexplained sounds in their residences and later developed physical symptoms,” the AP’s Josh Lederman said. “Americans who heard these sounds in Havana have described slightly different sounds. And even in some of the recordings that the AP has reviewed, there are slight variations. However, this high-pitched cricket sound seems to appear in all of them.”
George Washington University Professor Kausik Sarkar, who specializes in mechanical and aerospace engineering, listened to the recordings and told the AP it’s possible the piercing sounds could lead to physical damage.
“It’s like an acoustic hammer which is hitting you,” Sarkar said. “You’re just not able to hear it because its frequency is much higher. There were some concerns to it, and if it was really, really high, it could create some bioeffects.”
Listen to the high-pitch noises yourself in the video below:
First reports of the high-pitch noises and the ailments caused by them could point to some person or government agency targeting the United States’ intelligence network in Cuba.