A Hennepin County jail inmate tested positive for coronavirus Sunday, marking the first known case inside a Twin Cities detention center.

The man, who has not been identified by authorities, was booked into the jail on Friday and quickly isolated by staff after exhibiting symptoms. The inmate, who has not yet been charged with a crime, was released Sunday shortly after his results came back and has agreed to self-isolate at home, said Rob Allen, chief of staff for the Hennepin County Sheriff's Office. The nature of his alleged crime was not public due to privacy concerns, Allen said.

"We are optimistic that the steps that we have employed to prevent the spread will have been successful," the department said in a statement. "We continue to monitor those who may have been in contact with this inmate to ensure that the risk of contagious exposure is mitigated."

In recent weeks, county jails have moved to aggressively slash inmate populations to make room for potential quarantine space should an outbreak occur. Law enforcement agencies also suspended many jail bookings for nonviolent, low-level crimes that could easily be cited and released.

As of Monday, Hennepin County's daily jail population hovered at 470, down from roughly 800 inmates in February.

State prisons have been slow to follow suit, even as the virus explodes behind bars.

The respiratory disease spread to a third Department of Corrections facility Sunday. At Moose Lake prison, the site of the worst outbreak, twelve inmates have tested positive for COVID-19 and another 26 are presumed positive based on symptoms.

At least 13 DOC employees, at Moose Lake and the Red Wing juvenile facility, also self-reported falling ill with the virus.