WAUSAU — Police say a 56-year-old Athens man sexually assaulted a mentally ill woman at a Schofield assisted living facility after visiting a family member who is living at the home.

John Niemann faces charges filed Monday in Marathon County Circuit Court of second degree sexual assault of a mentally ill victim. During an initial appearance, Circuit Judge Greg Strasser ordered Niemann held on a $10,000 cash bond.

Police were called at 2:45 p.m. Friday to Copperleaf Assisted Living to investigate after two employees reported they had discovered Niemann naked in bed along with a resident there late the night before. Niemann is not himself a resident of Copperleaf, but was visiting a family member with dementia when the alleged assault occurred.

The alleged victim, whose age was not released, was declared incompetent in April 2017 and is unable to consent to having sex due to her diminished mental condition, according to court documents. The police report states that the woman is living at the facility for elderly assistance.

Niemann admitted being naked with the woman and told police he “made a bad decision,” but denied having sexual intercourse, according to the police report.

A preliminary hearing is set for March 7.