A California teacher is facing scrutiny after witnesses say she said the n-word 15 times and encouraged a student to do so as well while reading a Mark Twain novel.

The incident happened at Sequoia Middle School in Fontana, California, ABC 7 reported.

While the class was reading the book, one student came across the racial slur and chose not to say it out loud. The language arts teacher, however, repeatedly used the n-word and told the class that it was simply another word in the English language.

“The teacher got in front of the class and she was saying that ‘the word is just an English word and everybody can say it if she wants to, it’s in the dictionary, and people are oversensitive over the word,'” a student who recorded the incident on her phone told ABC7.

The witness added that the teacher “was trying to force him to say the word.”

“She repeatedly kept saying it and she had a smirk on her face. I was just thinking, ‘Dang, this teacher is out of her mind,'” the student said.

The teacher used the racial slur at least 15 times according to the witness.

The Fontana Unified School District said in a statement that the incident is under investigation.

“While we acknowledge that this derogatory language comes from a novel first published in the late 1800s, and that historical context is important to consider when discussing literature, the District does not condone the language that was used in the video or using that language outside of the context of discussing the novel,” the district stated according to KTLA 5.