The Tulsa County sheriff's Office says it is investigating allegations of sexual misconduct involving a school employee at Union Public Schools.
The district said it was notified more than a week ago of a possible inappropriate incident involving a high school student and an unidentified security guard.
The school district said the employee resigned during the course of the investigation.
Union Public Schools released a statement which said "the matter has been turned over to the Tulsa County Sheriff's office and the Department of Human Services."