The Chicago Police Department maintains a secretive facility where law enforcement allegedly house, interrogate, and abuse detainees in a style that's been compared to CIA black sites, according to a new investigation by the Guardian's Spencer Ackerman.

Homan Square, a warehouse on Chicago's west side, has long been used by secret police units, sometimes in operations that deny basic constitutional rights, people familiar with the facility told the Guardian. It's reportedly used by police for anti-gang, anti-drug, and counter-terrorism investigations.

The Guardian detailed several abuses: police interrogations without reading Miranda rights, lack of access to attorneys, keeping arrestees out of official booking databases, beatings by police, shacklings for long periods of time, and holding people — even children as young as 15 — without legal counsel between 12 and 24 hours. One man was reportedly found unresponsive in an interview room at Homan Square and later pronounced dead; it remains unclear why he was in police custody in the first place.

"It's a domestic black site"

Lawyers who try to access the facility are most often turned away — even as their clients remain in custody, the Guardian noted.

Many of these practices violate the Chicago Police Department's guidelines, which require officers to allow legal representation, grant "a reasonable number of telephone calls," and not delay the booking process due to investigations or interrogations, according to the Guardian.

Brian Church, who was held at Homan Square for 17 hours in 2012 after a police raid, compared the warehouse to the US's secret interrogation facilities for terrorist suspects around the world. "It brings to mind the interrogation facilities that they use in the Middle East," Church said. "It's a domestic black site."

Church was found not guilty of terrorism-related charges. He's currently on parole after serving two-and-a-half years in prison for possessing an incendiary device and a misdemeanor "mob action" charge, according to the Guardian.

Other people detained at the facility declined to speak to the UK-based news outlet, reportedly out of fear of police retaliation.

The Chicago Police Department, which has come under criticism for other abusive practices, didn't respond to the Guardian's questions about Homan Square. A former Chicago Police superintendent and a recently retired detective, both of whom were reportedly inside Homan Square in the past few years in a post-police capacity, told the Guardian that the department didn't operate at the facility until the late 1990s.

For more information, make sure to read the Guardian's full report on Homan Square.

Update: Chicago police denied many of the Guardian's claims. The Chicago Sun-Times' Frank Main reported the building isn't being kept secret: the public is able to recover inventoried property from the facility, and news conferences are regularly held at Homan Square. A spokesperson said police keep arrest records for the facility, although booking is done in other places. Police also claimed that the man found unresponsive in a Homan Square interview room died from a heroin overdose after allegedly buying drugs from an undercover cop.