Agee-Bell says her son might have been distracted or talking too much, but she say's Thole's comments crossed a line.
Thole did not respond to the publication's request for comment.
"I told her, 'The fact that you're a social studies teacher and you don't understand the racial implications of what you said to my son baffles me, '" Agee-Bell told ABC News.
Thole reportedly later apologized to the class for offending Nathan and stated that she did not have harmful intentions, but Agee-Bell is still pushing for change.More news: Bayern Munich confirm interest in Arsenal and Liverpool target Leon Goretzka
Mason School District told Cincinnati.com that its investigation found that Thole did indeed chastise Agnee-Bell's son using the words she is accused of using.
Later, Agee-Bell spoke with Thole.
Agee-Bell said she planned to speak during a school board meeting Tuesday night, but was asked by officials to talk privately afterward instead.
Carson praised Nathan for bravely confronting the teacher.
Lynching remains a racially sensitive topic as approximately 3,446 African-Americans were lynched between 1882 and 1968 as a way for whites to resolve racial tension, according to the NAACP.
Agee-Bell meant to speak Tuesday at a school board meeting, but she said officials asked to speak privately with her afterward - which she said lasted only five minutes, and the teacher's remarks were never mentioned in the public meeting.More news: Tamil Nadu bus strike ends after 9 days, normalcy restored
"For me, that's enough for her, as a social studies teacher especially, to be removed from the classroom", Agee-Bell told Fox 19. "That's not satisfactory at all", she said.
Agee-Bell had previously met with district officials, including the superintendent, in December. "We must ensure that ALL Mason City Schools' students are welcomed, valued and cared for while at school".
"And I'm not saying she should never go back in the classroom, but until she can demonstrate that she understands what the impact of the language that she used and what she did can have, has had on my son, has on his peers and is having on our community, then she doesn't need to be in the classroom".
"My son was walking around thinking he did something wrong", the mother explained.
She made a decision to speak during a school board meeting, but the officials asked her to discuss her concerns privately afterwards.
According to the Cincinnati Enquirer, Nathan did not tell his mother what happened for a week. As a district, we want to be very clear.More news: Cold staying around rest of this week
Few days ago, a youth basketball team in Warren County was banned from the league for wearing jerseys with racist names printed on the back.