A classic example of a double agent from the time of World War I is the legendary Mata Hari, recruited for espionage activities first by the Germans under the pseudonym "H21", and then by the French.
She was born on August 7, 1876.
From the French secret services, Margaretha Gertrude Seele, as the real name of the famous dancer of Dutch origin is, received 25,000 francs for each enemy agent she betrayed.
However, the French smelled her double game, initiated a trial on charges of espionage and sentenced her to death. On October 15, 1917, Mata Hari was executed.
Since none of her relatives came to collect her body, it was left for medical research, and the head was embalmed and kept at the Musée d'Anatomie in Paris. However, in 2000, it was discovered that the head was missing and that it may have disappeared as early as 1954, when the museum moved to a new location. There are documents from 1918 that indicate that the museum also received her remains, but these too could not be found.