An aggressive attempt by Montreal Metro inspectors to detain a man, just centimetres away from an oncoming train, has prompted calls for an investigation.

The incident was captured on video, which begins by showing two inspectors on the platform of the Villa-Maria Metro station on Thursday night. They are on top of a man who appears to be squirming to get free.

One of the officers grabs him by a leg just as he breaks loose. The man is on his back, and shouts in French: "Stop. It hurts."

Warning: Some viewers may find the following video disturbing.

CBC News has opted to blurr the man's face as he has not yet been identified. 1:08

At this point, his head is in the yellow area demarcating the danger zone closest to the track. The rumble of a Metro can be heard in the distance.

For a moment, the situation appears to calm down, though the inspectors are wielding their batons over their shoulders, poised to strike. As the man raises his knees toward his chest, the inspectors swat at his legs.

The oncoming Metro car sounds its horn. The man sits up, and raises his hands. The Metro cars are now behind his head.

With the inspectors swinging occasionally at him, the man gets up, darts around them, and runs away.

Samantha Gold, an eyewitness, said it appeared the inspectors 'moved too quickly to violence.' (CBC)

CBC News does not know the man's identity and has not been able to independently confirm what happened before the incident that is captured on video.

Samantha Gold, an eyewitness, said the man was holding a pink soccer ball on the platform when he was approached by the inspectors, who began to question him "aggressively."

Gold turned away for a moment, but turned back at the sound of a scuffle. "The next thing I see is this young man being slammed into the concrete wall," she told CBC News.

The person who took the video shared it with Gold, who in turn shared it with CBC.

'Man was bothering clients: STM'

In a statement issued Sunday, a spokesperson for the STM said the man was approached by inspectors because he was bothering other passengers.

"The client was hindering circulation and endangering the safety of clients aboard the train, in addition to not having paid for his ticket," said spokesperson Amélie Régis.

"He ran away and so wasn't arrested. An investigation will determine whether charges of obstruction will be brought against him."

Régis also said the transit agency doesn't believe the inspectors acted inappropriately, based on an preliminary review of the evidence.

But some public officials and minority-rights advocates who have seen the video want a more detailed explanation of the behaviour of the inspectors.

'There were a lot of issues of force, a lot of issues regarding physical safety. That should be the object of some sort of investigation,' said CRARR executive director Fo Niemi. (CBC)

"It's very disturbing as you can see, because of the way the man was beaten even when he was lying on the floor and not resisting," said Fo Niemi, executive director of the Center for Research-Action on Race Relations.

"There were a lot of issues of force, a lot of issues regarding physical safety. That should be the object of some sort of investigation."

For Gold, the eyewitness, it appeared the inspectors "moved too quickly to violence."

Snowdon Coun. Marvin Rotrand sent a letter to STM chair Philippe Schnobb Monday morning calling for an independent inquiry into the incident.

He said the results of his requested inquiry must be released to the public.

"This is a very troubling video," Rotrand said on CBC Montreal's Daybreak.

"It doesn't matter whether the rider, the citizen, is guilty of anything … the fact that he was hit five times after he displayed absolutely no hostility whatsoever, that's the important part."

He said he hears many complaints about the treatment of people of colour by STM security in the Villa-Maria station in particular.

One of the issues that deserves more attention, said Niemi, is the lack of oversight of Metro inspectors. He pointed out that they are not subject to the same accountability mechanisms in place for Montreal police assigned to Metro duty.

"Rarely have we seen such a visual, graphic display of force used against a Metro rider," said Niemi.

"We hope this man comes forward with his version [of what happened]."