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U S Secret Service
https://en.wikipedia.org/wiki/United_States_Secret_Service


It used to be part of the Treasury Department, devoted entirely to investigating counterfeiting of U.S. currency.
Since 1901, a portion of Secret Service has been assigned to protecting U.S. presidents. And has about 8,300 agents.

I was unaware till now that since 2003, Secret Service was moved to become part of the Department of Homeland Security (that is about as politicized and untrustworthy as the FBI).