Facebook, Instagram and Twitter have suspended Geofeedia, a platform that collects real-time social media information based on location, from having access to its data.

The decision follows an investigation that law enforcement used the tool to track activists and protests, the American Civil Liberties Union of North California (ACLU) published in a blog post Tuesday. It provides another case that surveillance information is potentially being used to target minority groups.

Geofeedia pulls social media feeds and makes it searchable and accessible to third parties (Mashableis a customer). Subscribers can search by keyword and by location to find recently posted and publicly available tweets.

The information is accessible at least 500 law enforcement and public safety agencies as of June, according to an email from Geofeedia published by ACLU.

Geofeedia, for its part, does not deny selling its data to law enforcement agencies. It noted "major law enforcement agencies like the Los Angeles County Sheriff's Department" as a subscriber in its Series A funding round announcement in 2014.

Yet, the ACLU investigation highlighted the tool's surveillance capabilities, which is against these social media platforms' rules. The ACLU posted emails from Geofeedia's team that mentioned the tool's ability to track the protests in Ferguson, Missouri, and Baltimore.

The confidential emails from Geofeedia published by ACLU also say that the platform is able to "pull private information for Instagram and Twitter users."

The ACLU reached out to the companies about the situation with Geofeedia. Additionally, The Daily Dotreported via a public record request that the Denver Police Department uses Geofeedia. The Baltimore Sunreported that its police also used Geofeedia to monitor protests, parades and celebrations.

Facebook and Instagram decided to cut off access on Sept. 19, shortly after being contacted by the ACLU. Twitter delayed until Oct. 11.

Tweet may have been deleted

Facebook's platform policy also states that developers cannot "sell license, or purchase any data obtained from us or our services” and they cannot “transfer any data that [they] receive from us (including anonymous, aggregate, or derived data) to any … data broker.”

Facebook said in a statement to Mashable, "This developer only had access to data that people chose to make public. Its access was subject to the limitations in our Platform Policy, which outlines what we expect from developers that receive data using the Facebook Platform. If a developer uses our APIs in a way that has not been authorized, we will take swift action to stop them and we will end our relationship altogether if necessary.”

Twitter said it forbids its data from being used "to investigate, track or surveil Twitter users," its developer policy reads. The company had previously cut off intelligence agencies from using Dataminr for surveillance reasons, the Wall Street Journal reported.

Update: Phil Harris, CEO of Geofeedia, released a statement at 5 p.m. ET Tuesday defending the platform's transparency and saying the company has clear policies that prevent "inappropriate use" of the software.

Geofeedia is a software platform that aims to provide important, real-time publicly available information to a broad range of private and public sector clients, including corporations, media and journalism groups, marketing and advertising firms, educational companies, cities, schools, sports teams, and the aviation sector. In each of these areas, Geofeedia is committed to the principles of personal privacy, transparency and both the letter and the spirit of the law when it comes to individual rights.

Our platform provides some clients, including law enforcement officials across the country, with a critical tool in helping to ensure public safety while protecting civil rights and liberties. Notably, our software has also been used in response and recovery efforts – from the Boston Marathon to the effects of Hurricane Matthew that we saw this past weekend – to assist millions of people affected by both manmade and natural events.

Geofeedia has in place clear policies and guidelines to prevent the inappropriate use of our software; these include protections related to free speech and ensuring that end-users do not seek to inappropriately identify individuals based on race, ethnicity, religious, sexual orientation or political beliefs, among other factors.

That said, we understand, given the ever-changing nature of digital technology, that we must continue to work to build on these critical protections of civil rights. Geofeedia will continue to engage with key civil liberty stakeholders, including the ACLU, and the law enforcement community to make sure that we do everything in our power to support the security of the American people and the protection of personal freedoms.