VANCOUVER -- CTV News Vancouver has learned a human resources investigation is underway into a Surrey high school teacher who screened a controversial true-crime documentary about a notorious Canadian killer in her classroom.

“I can confirm that they did watch inappropriate content in the class,” said Surrey School District spokesperson Ritinder Matthew. “Any further details are confidential as this is an HR investigation.”

The principal of Elgin Park Secondary School launched an investigation Monday after a parent filed a written, anonymous complaint to the district superintendent, claiming their child was traumatized “to the point of being hysterical and vomiting because students were made to watch a film called ‘Don’t Fuck with Cats.’”

The investigation has now escalated to the school district and its human resources department, which has not provided a timeline for its probe.

“No doubt many parents would be disgusted and horrified if they witnessed something so awful and so violent,” wrote the parent in the complaint obtained by CTV News. “Adding to the damage, our other children who were told about the incident are now also terrified that someone will steal our pets and torture and mutilate them.”

The three-part series was produced by Netflix, which has rated the material for mature audiences due to “disturbing images," and "animal harm.” The documentary features the efforts of amateur online sleuths trying to track down a mysterious man who kills and tortures kittens in YouTube videos. He goes on to kill a man in a subsequent video post.

The work of the amateur detectives eventually identified Canadian aspiring model and escort Luka Magnotta as the perpetrator. Magnotta was ultimately convicted of the murder of international student Jun Lin, who he killed in a Montreal apartment. The case spawned a global manhunt, as Magnotta mailed Jun’s body parts to political offices and Vancouver schools.

Several people claiming to be students in the class have contacted CTV News, insisting the teacher gave the Law 11/12 students ample opportunity to avoid watching the film and saying none of them objected.

“She always keeps it real and after being so sheltered by everyone else for years, the truth is what we need,” wrote one student.

Another wrote: “The teacher from this story is a very kind teacher who cares deeply about everyone in our class and has made it extremely clear that we could leave if we ever felt uncomfortable.”

But, child psychologist Alyson Jones worries that peer pressure and expectations could’ve stifled a teen that wasn’t ready to see the images and hear descriptions contained in the series. The films include images of dead kittens within the first 20 minutes, and they grow more disturbing with the introduction of the murder video in the second part of the series.

"We teach our children to be polite and if they're compliant and good students, then sometimes they won't speak up," said Jones. "I'm quite concerned there could've been students sitting there watching this not knowing how to say, 'No, I don't want to see this,' or, 'I'd like it to stop.'"

Since CTV News first reported on the complaint and the screening of the film on Tuesday, comments on the story have ranged from dismissal of the student’s reaction to outrage that the teacher would consider playing a film that many adults can’t stomach.

“We are in Law 11/12, [the teacher] told us at the beginning of the year that is wasn’t an easy subject and we knew what we were getting ourselves into,” wrote one student.

“We are old enough to make our own decisions.”