Karl Ferninand Braun

See: https://en.wikipedia.org/wiki/Karl_Ferdinand_Braun

"Braun went to the United States at the beginning of World War I (before the U.S. had entered the war) to help defend the German wireless station at Sayville, New York, against attacks by the British-controlled Marconi Corporation. After the US entered the war, Braun was being detained, but could move freely within Brooklyn, New York. Braun died in his house in Brooklyn, before the war ended in 1918."

That is the official story. He ended up defecting to the US, and assisted in developing advanced wireless telegraphy for use against the Cult of Thule, the group behind both Germany's involvement in World War 1, and the rise of the Nazi party.

Lives to be 100, dies in 1950. Thinks Tesla is a total asshole.