CHARLOTTE, N.C. (CBS Charlotte) — A teacher at Myers Park High is in custody and is accused of sexual activity with a student.

Over the weekend, CMPD obtained a warrant for Kristina Ngum, who later turned herself in at the Mecklenburg County Sheriff’s Office.

The student, who has not been identified, was arrested on Friday due to an unrelated drug charge.

Ngum, who is 43, graduated from the University of North Carolina at Charlotte in 2010.

Many parents assume that when they send their children to school, they are surrounded by upstanding teachers. However, this is the third time that Ngum has been arrested. According to Mecklenburg County public records, Ngum was arrested in July 2011 for false pretense and misdemeanor larceny. Additionally, county records show that Ngum was charged with a DWI in 2008.

The Charlotte-Mecklenburg School District initiates extensive background checks before hiring teachers. It is not known at this time if CMS was aware of Ngum’s previous arrests, or where or when the incident took place.

Ngum is expected to appear in court today.

-Nichole Jaworski, CBS Charlotte