Major Karl-Erich Kühlenthal (1908 – October 25, 1975) was a German spy and one of the most senior Abwehr agents in Spain during World War II.
Although the head of German intelligence in Spain was then Wilhelm Leissner, alias "Gustav Lenz"codename "Heidelberg", Admiral Wilhelm Canaris had taken a shine to Kühlenthal to the extent that Leissner was effectively superseded.
[1] Kühlenthal was a Mischling—"a half-blood Jew" with a Jewish grandmother, Canaris had managed to secure an Aryan certificate for him in 1941.
[a] In 1943, when the body of "Major William Martin"—a Royal Marine attached to Combined Operations—had washed up on a beach in Spain after a possible plane crash, Kühlenthal thought he had found important classified documents on the British major's body.
In fact, the documents were false and the body part of a fake persona to lend credibility.