Possible Culprit in Mysterious Havana Syndrome: Unit 29155

Last year, the US government declared that it could find no evidence linking a foreign adversary to the mysterious ailment striking diplomats known as Havana Syndrome. A joint investigation by the Insider, CBS News, and the German outlet Der Spiegel begs to differ and points the finger at Russia:
The investigation focuses on the Russian intelligence unit 29155, suggesting that it deployed some kind of sonic weaponry.
Among other things, journalist Christo Grozev of the Insider uncovered a bonus received by a 29155 officer for work on the “potential capabilities of non-lethal acoustic weapons.” Says Grozev: “It’s the closest to a receipt you can have for this.”