Exclusive: Secret interrogation facility in Chicago reveals creeping aspects of war on terror in US city as accounts describe shackling and brutality without basic rights.

The Chicago police department operates an off-the-books interrogation compound, rendering Americans unable to be found by family or attorneys while locked inside what lawyers say is the domestic equivalent of a CIA black site.

The facility, a nondescript warehouse on Chicago's west side known as Homan Square, has long been the scene of secretive work by special police units. Interviews with local attorneys and one protester who spent the better part of a day shackled in Homan Square describe operations that deny access to basic constitutional rights.

Alleged police practices at Homan Square, according to those familiar with the facility who spoke out to the Guardian after its investigation into Chicago police abuse, include:

• Keeping arrestees out of official booking databases.
• Beating by police, resulting in head wounds.
• Shackling for prolonged periods.
• Denying attorneys access to the "secure" facility.
• Holding people without legal counsel for between 12 and 24 hours, including people as young as 15.

At least one man was found unresponsive in a Homan Square "interview room" and later pronounced dead.