COLUMBIA, S.C. – Four inmates were found dead Friday morning in a dorm at one of South Carolina’s maximum-security men’s prisons, authorities said.

The inmates were found at Kirkland Correctional Institution in the capital city of Columbia, Department of Corrections Director Bryan Stirling told The Associated Press.

Stirling did not say how they died or release any further information, reported Fox News.

GovXStirling requested investigative assistance from the State Law Enforcement Division. Coroner Gary Watts confirmed he was investigating four deaths at the facility, but would not provide details about how the inmates died.

Kirkland operates a specialized housing unit for the state’s most dangerous inmates, an assessment and evaluation center for new inmates sentenced to more than three months, and a 24-bed infirmary, according to the Corrections website.

Like many prisons, Kirkland has seen violence.

In 2015 two inmates forced their way into a nursing station using homemade knives. Their goal was to obtain prescription drugs. They held two nurses hostage for seven hours, cutting the throat of one, but she survived.

Then last year, three corrections officers at Kirkland were fired after officials said they tried to kill an inmate in their care. Authorities said the officers, who were charged with attempted murder and misconduct in office, stabbed an inmate while he was handcuffed.

Their cases are still pending, according to Fox.