BAYPORT, Minn. (AP) -

The warden of the Stillwater state prison is on leave pending an investigation by the Minnesota Department of Corrections.

Officials are not releasing any details of the investigation. Department spokeswoman Sarah Fitzgerald confirms Steven Hammer has been on leave since Monday.

The Star Tribune reports he is still on the payroll.

Hammer previously worked as warden of the Rush City prison. He took over at Minnesota Correctional Facility-Stillwater in March of 2015.

Messages left for comment at various Hammer telephone listings were not immediately returned Friday. It is unclear if he has an attorney.