How did the Nazis spy?

The Nazis employed a range of espionage tactics, including the use of the Gestapo (secret police) and the SS to monitor and suppress dissent. They utilized informants, intercepted communications, and conducted surveillance to gather intelligence on individuals and groups deemed a threat. Additionally, they established networks of spies both domestically and in occupied territories to gather information on enemy movements and resistance activities. This extensive surveillance system enabled them to maintain control and execute their policies effectively.