Should the police monitor social media? The question seems to have an obvious answer. Social media, says Joe Giacalone, a retired New York Police Department detective who now teaches at John Jay College, is “a treasure trove for investigators. People post stuff they shouldn’t…vehicles, weapons, you name it. If you’re dumb enough to post something on social media and you’re wanted for a crime, you deserve to get caught.” In this sense, social media is no different from any other public space. If criminals brag about or plot their exploits publicly online, police should be able to use that information without obtaining a warrant, just as if they overheard chatter in a bar or on a street corner.
But there is a difference between an individual officer looking at posts from someone suspected or accused of a specific crime, and the sort of mass monitoring made possible by data-scraping and automated surveillance. There is also a difference between looking for evidence of criminal activity and monitoring politically unpopular, but still legally protected, speech. Records obtained by the American Civil Liberties Union of Northern California (aclu-nc) revealed that in 2015 a police department in Fresno used a social-media monitoring firm that boasted it could “avoid the warrant process when identifying social-media accounts for particular individuals,” and could “identify threats to public safety” by monitoring terms including “policebrutality”, “wewantjustice”, “Dissent” and “Blacklivesmatter”. Other law-enforcement agencies in California used a similar service whose marketing materials referred to “unions [and] activist groups” as “overt threats”.