A Wisconsin woman, a former teacher, is charged with sexual assault after allegedly having an affair with her daughter's 13-year-old former boyfriend.

Thirty-nine year old Anne Knopf of Prescott, Wisconsin was charged with Sexual Assault of a Child Under 16 in Pierce County District Court Monday.

The charge is the result of a four-month investigation into the relationship between Knowpf and the boy. The boy's parents became aware of the relationship and notified police in mid May.

She has been released on $25,000 bond. Knopf has been ordered to refrain from contacting the victim. She retained custody of her two children.