How common was it for the FBI to use major criminals as informants for completely unrelated investigations?
I recently went down a rabbit hole about Gregory Scarpa and his relationship with the FBI.
Scarpa was a major figure in the Colombo crime family while also working as an FBI informant for years. What surprised me was learning that the FBI brought him to Mississippi for special assignments connected to KKK violence during the Civil Rights era.
So you basically have federal law enforcement relying on someone involved in serious organized crime to help obtain information in a completely different world.
I originally learned about Scarpa because Mark Wahlberg is playing him in By Any Means but the real history ended up being much more interesting to me.
Was using someone like Scarpa unusual for the FBI at the time? Or are there other examples of major criminals being used for investigations that had nothing to do with their own criminal organizations?