An investigation into allegation that a high school teacher in Whitby, Ont., referred to a group of black students as a "n--gerfest" has ended with no punishment for the teacher, according to a parent who attended a meeting with the Durham District School Board.

"I'm extremely frustrated," said Jennifer, a parent whose son was one of the targets of the alleged slur. CBC News is withholding her last name to protect her son's identity.

"That's not going to be a good learning environment for my son. His grades have suffered. He doesn't want to go to school anymore, so I think he needs a fresh start."

Jennifer, the mother of a student at the high school plans to pull her son from the school because the board won't remove the teacher. (CBC)

Jennifer said because the DDSB won't transfer the teacher to a different school, she's pulling her son out.

CBC News has repeatedly asked the board for an update on the investigation. In response, it sent a statement saying the investigation into the alleged racial slur "could not be conclusively substantiated following a comprehensive and thorough analysis of the available evidence."

Investigation compromised

A Grade 10 female student at Donald A. Wilson told CBC News a group of black, male students was denied entry to the gym on Feb. 13.

She asked not to be identified.

As the Grade 10 student and another female student left the gym to join the boys, she said she heard the teacher who barred the boys from the gym say, "The place was turning into an n--gerfest."

She immediately reported the slur to the vice-principal.

Three months later, the school board informed parents of the students involved that it had hired Laura Williams of Williams HR Law to investigate.

The law firm sent out letters to parents of the students involved on May 5 asking them not to speak to any third party about the incident.

There's still no validation that their concerns are real, that this did happen, that this was wrong. - Mother of student who was a target of alleged slur

Jennifer said in the meeting, the DDSB admitted it had waited too long to look into the allegation and because of that, and CBC's reporting on the allegation, the investigation's integrity was compromised.

"This is not the resolution I wanted," she said.

In its statement, the DDSB said it has already begun implementing some of the lawyer's recommendations when it comes to similar incidents including: staff training on the investigations process, and "develop and implement policies, protocols, guidelines and procedures to assist school administrators with determining how to respond to allegations of this nature."

"I'm encouraged going forward for the kids who have issues going forward, but for my child, at this point, I'm not encouraged," said Jennifer. "There's still no validation that their concerns are real, that this did happen, that this was wrong."