A female employee was fired from Cardigan Mountain School earlier this month for sexual misconduct.
Kimberly Wennik was the manager of the school store and mail room and admitted to having "sexual contact" with a student at the all-boys boarding school, according to school officials.
The school sent a letter to students' parents on July 10 notifying them of the situation. School officials say Canaan police are investigating the matter.
Cardigan Mountain is a boarding and day school for boys in sixth to ninth grade.
This allegation comes at a time of increased scrutiny of sexual misconduct at private boarding schools across New England, including at St. Paul's School in Concord. The New Hampshire Attorney General's office named a compliance overseer to St. Paul's last December.