The sister of a man whose violent arrest by an Edmonton police officer was partially captured on video is calling for an investigation into the incident, and for the officer's resignation.

"My family's calling for this officer to resign and for him to be investigated," Monica Biar told a news conference Friday.

The family has chosen to not release the name of Biar's younger brother, who suffers from undiagnosed mental health issues.

A three-minute video recorded by a neighbour shows the tail end of the March 25 arrest.

It shows a lone police officer trying to immobilize a man on the ground. The officer yells at the man to get on his stomach. The man doesn't comply.

A suspect is arrested by an Edmonton police officer in a downtown neighbourhood. 2:47

A struggle ensues, and the officer punches the man several times. The man punches back.

"Stay the f--k down," the officer yells.

"F--k off," the man responds.

"I'm going to f--king shoot you, stay down," the officer yells back.

The man then puts his hands in the air while the officer is pinning him down.

"Stop moving or I'll f--king shoot you in the face," the officer yells again.

Sirens can be heard blaring in the distance. More police then arrive and arrest the man.

Biar said she called police that morning when her brother started behaving strangely.

The family had called the police three weeks earlier to get help dealing with the young man's behaviour.

Biar said the earlier interaction was positive.

"The police told us three weeks ago that if the same incident happened again we should call them to come and take him in to get the treatment he needed, so that's exactly what I did," she said.

Monica Biar says she called police to get help for her brother, who has mental health issues. (Craig Ryan/CBC)

"After seeing the video, I could have gotten my brother killed."

She said she tried to tell the officer that her brother wasn't in his right mind, to no avail.

"I called the police for my brother to get help, not for him to be a punching bag for this police officer."

A statement from the Edmonton Police Service about the altercation contradicts Biar's account of what transpired.

"When the officer attempted to arrest the accused, the man resisted and became belligerent," wrote spokesperson Patrycja Mokrzan.

"The officer reported that the accused punched him in the face several times, and he then called for backup."

Police were responding to a call of a family dispute, Mokrzan said.

"It was reported that the accused was inside the residence and was assaulting his mother and sister."

Neighbour heard commotion

The video was shot by Brett Commandeur, who said he heard a commotion outside and started filming.

"I just wanted to capture it in case anything happened," Commandeur told CBC.

He said he didn't see what led to the altercation.

"He's shouting these things, and it's stressful and scary," he recalled. "It makes me think that there has to be other de-escalation tactics that can be used."

Commandeur questioned why the officer responded to the call alone.

"It makes you wonder what could have happened."

'They both started punching each other'

Another neighbour, Mary Both, said she watched the entire scene from her fourth-floor balcony.

Her account differs from the official statement provided by the police.

Both said the officer and the young man were talking to each other outside of the apartment building.

They started struggling when the officer attempted to arrest him, Both said.

"The police approached him, tried to arrest him, and grabbed him by the shoulder to try to lay him down," she told CBC.

"When they were down, they both started punching each other."

She said she called 911 when the officer started yelling for help.

"I didn't want anyone to get hurt."

Family to file complaint

Monica Biar says her brother had cuts and bruises following his altercation with an Edmonton police officer. (Monica Biar)

Biar said her brother suffered cuts and bruises during the altercation.

She's planning to file a complaint against the officer involved.

Her lawyer, Amanda Hart-Dowhun, told reporters that the video didn't show the whole incident, but contained disturbing elements.

"For a large portion of the video, you can see that the gentleman has his hands up in the air," Hart-Dowhun said.

"The officer is still screaming at him, and is threatening to shoot him in the face."

The man was charged with assaulting a peace officer while resisting arrest, said police.

Biar is calling for any charge against her brother to be dropped.

With files from Andrea Ross

