A report by the American Civil Liberties Union of Northern California reveals how nearly 500 police departments use mass surveillance tools to monitor the social media accounts of activists.

Former national security contractor Edward Snowden, who is currently a guest fugitive residing in Russia since 2013, outed the U.S. federal government’s use of the National Security Agency’s XKeyscore analytical tool to collect “almost anything done on the internet” by U.S. citizens. Snowden commented, “I, sitting at my desk [could] wiretap anyone, from you or your accountant, to a federal judge or even the president, if I had a personal email.”

According to the new records uncovered by the ACLU, police departments across the U.S. are monitoring Twitter, Facebook, and Instagram social media accounts through real-time, location-based user data analytic tools developed by Chicago tech firm Geofeedia, including “Geofeed.” The ACLU report states that “we have seen marketed to law enforcement as a tool to monitor activists and protesters.”

The Northern California ACLU office claims that they first learned about law enforcement “agreements with Geofeedia from responses to federal and state Freedom of Information Act public records requests to 63 California law enforcement agencies.” The records revealed a rapid growth in social media surveillance with “little-to-no debate or oversight.”

As ACLU representatives combed through “thousands of pages of documents,” they learned through police email exchanges that Geofeedia representatives marketed their services to law enforcement based on “special access to Twitter, Facebook, and Instagram user data.”

One message detailed special arrangements that Geofeedia had negotiated with Twitter and Instagram to access their “Firehose” to gain unlimited access to all user data.

Geofeedia also trumpeted that they had just entered into a “confidential legally binding agreement with Facebook” that will allow “reactivating more and more data to Geofeedia throughout our partnership.” The company added, “this data is far more data than any other competing data mining software has to offer when it comes to Facebook.”

As an example of the breadth and intrusiveness of its analytic tools provided to law enforcement, Geofeedia revealed how they “covered Ferguson/Mike Brown nationally with great success.”

After Michael Brown was shot and killed by a white police officer two years ago in Ferguson, Mo., Geofeedia was able to monitor the social media activities of Darren Seals, who was one of the most vocal activists leading protests across the city. Seals rallied a boycott of Democratic candidates in local elections after he said they failed to protect black lives. When a grand jury later declined to indict Ferguson police officer Darren Wilson, the press reported Seals holding Brown’s mother in his arms as she sobbed.

Darren Seals was found shot dead in a burning car on September 7, 2016 just outside Ferguson, according to reports by the St. Louis County Police Department.

The ACLU report claims that nearly 500 law enforcement agencies — including the Oakland Police Department — gained access to user data from at least eight social media sources through Geofeedia.

Malkia Cyril, executive director of the Center for Media Justice activist group in Oakland, told the San Francisco Chronicle, “At every protest, we assume we’re being spied on, because we know we are.” She added: “We assume whatever surveillance tools are at the disposal of our local police department, they’re being used.”

Although Geofeed data can allow law enforcement agencies to track protests as they happen and identify individuals involved, the ACLU report did not specify which data is being accessed by different police departments and how that data was used.

The extent to which police can use mass surveillance is a matter of ethical and legal dispute. But with social media companies selling their users’ most intimate secrets to advertisers for big bucks, it should not be surprising that law enforcement would become another major buyer of data to monitor individuals, groups and even entire cities.

Breitbart News contacted several conservative leaders to obtain their input on the ACLU report. Paul Preston of the nationally syndicated “Agenda 21 Radio Show” commented that this issue should also be of major concern to conservatives and libertarians.

Following the ACLU report, Twitter, Facebook and their Instagram division have severed their contractual relationships with Geofeedia.