sergeants benevolent association
Ed Mullins clashed with city officials over his bombastic tweets and hardline tactics.
The agency said the raids were part of "an ongoing investigation."
The FBI considers the far-right QAnon conspiracy movement to be a potential domestic terrorism threat.
The threatening statement came after two officers were shot in separate targeted attacks in a span of 12 hours.
WHAT'S HAPPENING
Memo calls officials fighting for police accountability "inept and spineless."