In 2006, the counterterrorism division of the FBI released a report warning of the widespread infiltration of white supremacists in law enforcement. The report specifically references incidents in Los Angeles, Florida, Chicago, Cleveleand, and one Texas sherriff’s department where officers had been fired after their ties to white supremacists groups were discovered. (4) In 2015, the San Francisco Police Department fired seven officers after communications were discovered showing allegiances to white supremacists ideologies and expressing their desire to lynch Black folks. In 2016, the SFPD offered those officers their jobs back. (5) Since the FBI counterterrorism report was released in 2006, the amount of white supremacists groups has over quadruple. (6)
http://www.dailykos.com/story/2015/5/21/1384553/-2006-FBI-Report-on-White-Infiltration-of-Law-Enforcement-You-Will-Be-Assimilated