A Massachusetts teacher is on administrative leave after he held a mock slave auction during a history lesson for his fifth-grade class. The teacher, according to WBUR, also used the N-word in class in a separate incident. In an email sent to parents on May 29, Superintendent Gregory Martineau apologized for the troubling incidents that happened at Margaret A. Neary School.

“I apologize for the events that took place in The Public Schools of Southborough,” Martineau wrote, per WBUR. “I acknowledge that there are missteps in this process that further complicated the situation.”

The teacher was teaching about the “economy of southern colonies” when he held the slave auction, the superintendent stated in the email to parents.

“During the lesson, the educator held an impromptu mock slave auction. The educator asked two children sitting in front of the room, who were of color, to stand, and the educator and class discussed physical attributes (i.e., teeth and strength),” his email read, per WBUR.

The same teacher used the N-word while discussing a book he was reading for his class, per the district. According to Martineau’s email, the book “was not part of the fifth-grade core English language arts curriculum.”

“It was later brought to the District’s attention that the ‘N-word’ does not appear in the book,” Martineau’s email continued. “Dehumanizing words such as slurs should not be spoken by employees or students. Using such words can harm students and negatively impact an open discussion on a particular topic.”

Meghan Cifuentes, who is a parent of one of the students in the class, told WBUR that her child came home and said the teacher used a bad word.

“Never was I expecting the N-word to come out of his mouth,” Cifuentes told the news outlet. “If you’re going to use that word with 10 and 11 years olds, there needs to be a heavy discussion of what the word is, why it was used and what it means — just some background information.”

According to Cifuentes, the N-word doesn’t appear anywhere in The Parker Inheritance, per WBUR. Martineau said the Northborough-Southborough District is developing a plan that focuses on “culturally competent pedagogy.” He also said the goal is to improve internal reporting and procedures for investigations.