A student group at York University is "outraged" after it says an interaction with a loss prevention officer employed by the Shoppers Drug Mart store on campus sent a student to hospital on Friday with his leg badly twisted.

Video of the incident, posted to the York University Black Students' Alliance Facebook page Saturday, begins with a man lying on the ground outside the store's entrance, screaming in pain, surrounding by a group of onlookers with multiple security guards nearby.

"Help me!" the man yells repeatedly, his leg appearing limp and resting at an awkward angle.

"Yes, an ambulance is on the way," someone can be heard saying in the just over two-minute-long video.

"I saw him being tackled," a person can be heard saying off camera.

In a statement accompanying the video, the Black Students' Alliance says the incident took place Friday morning around 9 a.m., and involved an "altercation" between a plainclothes officer working for the company. The officer, it alleges, tackled the student, leaving his leg twisted "at a 90 degree angle."

York University says it became aware of the "troubling incident" at York Lanes, the university's on-campus shopping mall on Friday, and has launched an internal investigation with its tenant, Shoppers Drug Mart.

"We understand that many members of our community have questions, including the University," it said in a written statement. "We are awaiting further details and will not presume the outcome of any investigation."

It's unknown what led to the altercation, but loss prevention officers are generally employed to prevent theft.

Toronto police confirm they were called to the scene Friday morning, where a man was being held.

A 25-year-old man was arrested and faces four charges including: theft under $5000, possession of property obtained by crime, assault with intent to resist and assault. The man was taken to hospital with a twisted ankle injury that occurred during the altercation, Const. Caroline De Kloet said.

As for whether the loss-prevention officer faces any charges, Const. David Hopkinson said, "It is always a possibility for anyone, police or loss prevention if someone is treated unfairly," but couldn't say if that was case in this incident, saying it is still under investigation.

No one from the on-campus Shoppers Drug Mart location would respond to CBC Toronto's requests to discuss the incident on Saturday. Staff Saturday evening said the manager felt it was too soon to comment on what happened.

In a statement, the company's vice-president of external communication Tammy Smitham said Shoppers Drug Mart stores often employ third-party loss-prevention officers to help deter and identify theft.

"We never encourage physical interaction between loss prevention representatives and individuals in our stores," Smitham said, adding the company will conduct a "thorough investigation" of the incident.

The alliance meanwhile, alleges that procedures to ensure student and staff safety were not followed Friday.

"The LPO (loss-prevention officer) executed their own brand of justice where they had no jurisdiction to do so," it says on Facebook. "They are not paid to place their hands on folks who come in and out of the stores they are hired by."

The statement goes on to say that university security arrived at the scene but could do little to assist, due to a policy between York University Development Corporation and private companies that operate on campus that gives York security no jurisdiction on retail properties.

That policy, says the alliance, is "extremely concerning." "This could've happened to any other student in any other facility within York Lanes," it says.

The university says will share more information as it becomes available, but that student and community safety are its first concern.

"Acts of violence are not tolerated. We will review policies related to private security employed by University tenants," it said in its statement.

In the meantime, the student alliance is calling for a boycott of Shoppers Drug Mart in light of the incident. No one from the Black Students Alliance responded to CBC Toronto's request for an interview.