News outlets report 26-year-old Mario McIlwain of Rock Hill, South Carolina, is accused of assaulting the girl from February until May at a middle school in Charlotte.
Charlotte-Mecklenburg police say the girl's mother notified them June 21 about the assaults.
A police statement said an investigation resulted in 27 warrants against McIlwain. He's charged with sex acts by a custodian, statutory rape and indecent liberties with a child.
The school system said McIlwain's employment ended Tuesday. It was not known if he has an attorney.
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