A Russian GRU military intelligence unit behind attacks across Europe may have used acoustic weapons against scores of U.S. diplomats and spies around the world, according to a new investigation by The Insider, 60 Minutes and Der Spiegel, shedding light on unexplained health incidents known as “Havana Syndrome.” Havana Syndrome’s name dates back to 2016, when U.S. diplomats in the Cuban capital reported falling ill and hearing piercing sounds at night, sparking speculation of an attack by a foreign enemy using an unspecified sonar weapon. To date, more than 100 reports of the illness — formall…