(Fond du Lac) An investigation is underway as the Fond du Lac Medical Examiners Office is looking into the death of an inmate at Fond du Lac County Jail. On Friday evening, shortly before 11pm correctional staff found the adult male inmate unconscious and not breathing in his cell. Staff began life saving measures with resuscitation efforts being unsuccessful. The inmate was then pronounced deceased. According to authorities the inmate did suffer from pre-existing medical conditions and was housed in a medical cell, however the cause of death is still undetermined until the Medical Examiner completes his investigation. Assisting the staff at Fond Du Lac County Jail was the Fond du Lac Fire/Rescue. The inmates name and age are being withheld at this time.