Agee-Bell has since had her son removed from Thole's class.
'First, I thought, my son misunderstood the teacher, he must have misunderstood the teacher, but she confirmed that that was exactly what she said.
The officials thanked Agee-Bell for coming, assuring her such issues are taken seriously - something she didn't believe.
Renee Thole, a white social studies teacher at predominantly white Mason Middle School who made the comments to the 13-year-old male student in December, won't be disciplined, but has been reprimanded and and will be required to attend cultural proficiency training, the Mason City School District said Thursday.
"As educators, sometimes we mess up".
Between 1882 and the height of the civil rights movement almost a century later, more than 3,440 African-Americans were lynched in the US, according to the NAACP's website.
After Nathan told his mother, she contacted Thole for an explanation - which she said was worse than her son reported.
According to Agee-Bell, she reached out to Thole seeking clarification.
"I told her, 'Next time you're frustrated are you going to call him a n*****?'" the mom told the Cincinnati Enquirer.
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"You shared that you realized that you cannot take that moment back but can only strive to make it a teachable moment for you and the students with your actions", reads the letter of reprimand, which the school district released to ABC News.
"For her not to understand that the words that she said were a direct pull from what has been, what was a practice in the United States, is unacceptable", Agee-Bell said, according to WLWT.
Tanisha Agee-Bell, the boy's mother, admits her son is a talker and something of a class clown, but rightly insists the teacher went overboard.
"I don't believe them", she said afterward. "That's not satisfactory at all", she said.
Thole did apologize to her class, which is mostly white students, and said her intentions were not harmful, cincinnati.com reports.
"My son was walking around thinking he did something wrong", she told the newspaper, crying.
"The hardest part is that even though he knows he did nothing wrong, he still is punished because he lost opportunity with his friends", Agee-Bell said. However, she said the district "investigated, documented, and set expectations for (the) future". She said two other children, whose parents are also in the council, have suffered racial discrimination in the last few months as well.
Agee-Bell plans to return to the next board meeting. School employees praised the event using the hashtag #MasonShines.
News of her son's experience came only days after a neighboring youth basketball team in Warren County was kicked out of its league for putting racist names on the back of their jerseys. If asked to discuss her concerns privately, she says she will refuse.