Brighton police said they launched a criminal investigation after learning about an allegation of misconduct regarding a staff member at McQuaid Jesuit High School.
Chief Mark Henderson said the investigation showed that a female staff member at the school had a consensual relationship with a 17-year-old male student in 2016.
Henderson said based on the student's age and the consensual nature of the relationship, the Monroe County District Attorney's office determined that no criminal charges could be brought.
Police said the staff member would not be charged with endangering the welfare of a child, a misdemeanor, because the statute of limitations had expired.
Henderson said no additional students are believed to be involved.
McQuaid issued a statement saying the faculty member, who was not identified, is no longer working at the school. The statement said the school could not comment on the specifics of the investigation.