Final answer:
The Sicherheitsdienst (SD) or the Security Service in Nazi Germany was headed by Reinhard Heydrich until his assassination in 1942.
Step-by-step explanation:
The Sicherheitsdienst (Security Service) or SD was an intelligence agency of the SS and the Nazi Party in Nazi Germany. Among its roles were enforcing the ideology of the Nazi Party and suppressing opposition to the Nazi Party. Reinhard Heydrich was the head of the Sicherheitsdienst until his assassination in 1942.
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