Thirteen House Democrats, concerned by how little is known about law enforcement’s surveillance of platforms like Facebook and Twitter, have written a letter to Attorney General Jeff Sessions demanding information.

“While social media data can be a useful tool for apprehending criminals in cases related to property destruction, human trafficking, and homicide, it can also be misused in ways that implicate Americans’ rights to free speech and freedom of association, as well as what the Supreme Court has recognized as the evolving Fourth Amendment right to privacy in our digital age,” wrote the representatives, who include Keith Ellison, Barbara Lee, Mark Takano, and Pramila Jayapal.

From Occupy Wall Street to Black Lives Matter to protests of the inauguration of Donald Trump, demonstrators have long been monitored by law enforcement on social media. There have even been arrests made as a direct result of that monitoring.

The letter focuses in part on data tools that law enforcement has used to find information — some of it not necessarily public — among metadata from Facebook, Instagram, and Twitter. Last October, the American Civil Liberties Union of California reported that law enforcement agencies were using a social media monitoring service provided by the developer Geofeedia to view data that may otherwise have required a warrant, including location information. After the revelation, all three social media companies rolled back Geofeedia’s access to their data.

The Congressmen are asking Sessions for answers to 11 questions that focus largely on the government’s duty to protect citizens from undue police intrusion and surveillance. One question asks, “What measures are in place to prevent an undue amount of scrutiny on communities of color, religious minorities, or immigrant and refugee communities?” Another demands to know how much money the Department of Justice has given to local law enforcement agencies for social media monitoring. A third asks how long collected data is stored.

The questions likely won’t get a warm reception. Sessions is a staunch ally of law enforcement and has long been a proponent of digital surveillance. While a member of the U.S. Senate, Sessions was a stalwart defender of the Patriot Act, and he stymied efforts to require law enforcement to get a warrant before accessing emails. More recently, he ordered the DOJ to review agreements with local police departments, known as consent decrees, which required police to reform their practices after being investigated by the agency’s Civil Rights Division.