A south-central Idaho charter school says a teacher being investigated amid reports of a student's mouth being taped shut has resigned.

The Times-News reports that Xavier Charter School administrator Gary Moon made the announcement Thursday.

The instructor's name hasn't been released.

Moon says administrators immediately began an investigation after learning of the allegations in a second-grade class on Feb. 16.

The school says a substitute teacher with a bachelor's degree in education and a current Idaho teaching certificate has been filling in.

The school says that teacher will remain with the class until the end of the school year.