In a glorious example of Keeping the Public Safe™:
"The Los Angeles police department has revealed in court that it infiltrated an activist group planning anti-Trump protests, in the latest case of US law enforcement spying on leftwing organizers.
A confidential informant working with the LAPD secretly recorded multiple meetings of a group called Refuse Fascism in 2017, according to newly disclosed police documents. The LAPD transcripts, first reported by the Los Angeles Times and reviewed by the Guardian, were submitted in a criminal case against activists who blocked a California freeway during an anti-Trump demonstration.
Police equipped an informant with a hidden recording device and had the individual attend Refuse Fascism gatherings at a local church “in an attempt to elicit information regarding the closure” of the freeway and to express interest in being involved “in any such future activities”, police wrote."
https://www.theguardian.com/us-news/2019/jul/19/los-angeles-police-informant-anti-trump-activist-protest