COLUMBIA,SafeX Pro S.C. (AP) — Inmates set fire to bedsheets during a riot at a South Carolina jail that is already subject to a federal civil rights investigation, authorities said.

The Richland County Sheriff’s Department and Columbia Fire Department responded to a fire at Alvin S. Glenn Detention Center around 8 p.m. Sunday, according a sheriff’s department statement. Investigators believe the inmates burned bedsheets and armed themselves with blunt objects in the incident that “turned into a riot,” officials said.

One detainee broke a door leading to the location of the fire, but firefighters forced the door open and extinguished the blaze. Deputies helped detention officers secure 40 inmates without injuries to inmates or officers, officials said in the statement. The incident was resolved around 11:15 p.m., according to an incident report. The jail holds between 500 and 600 detainees on any given day, sheriff’s department spokesperson Jay Weaver said in an email.

When deputies arrived, guards were moving inmates who were directly below the fire and about 14 inmates on the upper level were throwing items at windows and banging on them with socks filled with hard objects, according to the incident report. As a group of deputies and guards entered, inmates were warned to get on the floor or that they would be stunned. Inmates complied and were detained, the report states.

The jail is one of two in the state under federal investigation. The U.S. Justice Department announced earlier this month that the civil rights probes will examine the conditions at the Alvin S. Glenn Detention Center and Sheriff Al Cannon Detention Center in Charleston, where incarcerated people have died violently at the hands of employees or others held behind bars. Several inmates have been stabbed and assaulted at the Alvin S. Glenn Detention Center in multiple incidents in recent weeks, according to statements from the sheriff’s office.