NEW YORK (CBSNewYork) — A Bronx teaching assistant is facing criminal charges after allegedly raping a mentally ill teenager.

Maria Contreras, 29, has been charged with six counts of rape and two counts of criminal sex act. She is expected to face a judge Sunday at Bronx criminal court, CBS2’s Ilana Gold reported.

Contreras has been fired over the allegations.

Contreras was a teacher’s assistant at the Bronx Academy of Letters, a public middle and high school. The victim is a mentally ill 14-year-old boy who is believed to be a student at the academy, police said.

Contreras raped the teen multiple times at her apartment on Barker Avenue in the Bronx, investigators said. The inappropriate relationship started Nov. 11 and lasted about a week, police said.

The victim told his mother about the alleged abuse, and she notified police.

The city Department of Investigation released a statement saying: “These allegations are incredibly disturbing. Ms. Contreras has been removed from her position and will no longer be employed by the DOE. We are working with the NYPD on their investigation.”