Demonstrators protest outside a Chicago Police facility on the city's Westside on February 28, 2015 in Chicago, Illinois - Getty Images

Over 100 activists from groups like the hacktivist collective Anonymous and the Black Lives Matter movement gathered on Saturday to protest the Homan Square facility.

The facility has been at the center of a Guardian investigation that revealed several allegations of unconstitutional abuse and sparked the hashtag #Gitmo2Chicago and leading to it being termed a “black site” by protestors.

“Rahm Emanuel says, ‘Trust us, we are doing the right thing,’” said organizer Andy Thayer of the Gay Liberation Network. “But I’m sorry, Mr Mayor, you have lied to us about enough other things that we are not going to take your word for it that things are just hunky dory in the building behind us. We demand that you shut down this facility.”

Reverend Gregg Greer, of the Southern Christian Leadership Conference, called for more people to come forward. “If the Chicago police department hasn’t gotten anything to hide,” he said, “then open up the doors!”

One protest leader, Travis McDermott, noted that the National Defense Authorization Act (NDAA) was the main reason facilities like this existed. Under the NDAA, people suspected of terror can undergo military detention.

“The main issue,” he said, “is that when individuals are empowered by a contract they have no threat of accountability, they can’t be expected to exercise self-restraint. They can deny and then it’s a battle of confidence between the people who have witnessed it and those protecting it.”

Activists have called for a public inspection of the facility along with access for detainees to a phone and a lawyer and printed notices of detainees’ rights throughout the facility.