A man who filmed children attacking a woman in Saskatoon says he made the hard decision not to intervene because he was concerned about potential implications on his permanent residency application.

The graphic video of the assault went viral. Viewers expressed shock and dismay at the violence, but also raised questions about why the man who filmed it did not step in to help the victim.

The 29-year-old from Africa contacted CBC to explain what happened. CBC agreed not to name him because he fears for his safety.

On Friday, Saskatoon police charged a 13-year-old girl with two counts of assault. One relates to an alleged attack May 13 at Pleasant Hill Park, and the second to the assault captured on video. In a news release, police said there were number of other youths identified as being involved in the assaults but, because they are under the age of 12, no charges will be laid.

The 13-year-old appeared in youth court and was released into her parents' custody and will return to court in June.

The girl indicated in court that she understood her release conditions that include having no contact with 12 children identified as either persons of interest or suspects in the alleged assaults.

Bonnie Halcrow says she was attacked when she began recording a group of young boys throwing rocks at an older man. It happened Monday in Pleasant Hill Park in Saskatoon. 0:26

The witness said he'd gone to the inner-city park to meditate and read. He came to Canada in 2010 and was two days away from getting his permanent residency, the culmination of a nine-year journey .

He had a lot on his mind, he'd had a rough day and just wanted to gather his thoughts before heading to work.

Then he said he saw "kids throwing stones at a guy that was going by. I was like, 'Stop that. That's not right. That's not a very nice thing to do.'

"And the kid was like, 'You're not my dad.'"

Then, Bonnie Halcrow and her 10-year-old daughter arrived. The 33-year-old from Flin Flon, Man., was in town visiting and came to Pleasant Hill Park so that her daughter could meet a friend.

Halcrow says the attack, witnessed by her child, left her bruised and shaken. (Dan Zakreski/CBC)

Halcrow witnessed the stone throwing and began recording the boys with her phone.

The 29-year-old man said he was also hit by a stone and the children shouted racial slurs at him.

The man said he made some fast and hard choices. He weighed the desire to lash out physically against possible legal implications of touching a child, and whether it could affect his residency.

"It took everything in me not to react," he said.

Children swarm woman

The man ignored the stone throwing.

At one point, he says one of the children came over and began filming him.

"Right in front of my face, he was taking a Snapchat video and calling me a pedophile. Again, it took everything in me not to react."

And then he said the group turned their attention to Halcrow.

"I think it was just one kid that started it — tried to throw a punch. I'm not really sure what happened. The lady was trying to defend and before you knew it, she was on the floor," he said.

"She was on the floor and that was it. She lost her glasses; she couldn't see."

Again, a hard choice.

"I'm thinking in my head, should I go there? Because I know, if I hit one of those children … I'm thinking about my status here in Canada," the man said.

"It took everything in me not to react when that lady was being beaten. I was so angry, I was at the point I was going to do something."

The man decided that the best thing he could do was to record the assault.

If I didn't do this, no one would have known about it. - Man who filmed assault

The attack was over in less than a minute. The man recalls Halcrow's daughter crying, and the woman trying to find her glasses.

After she left, he said the group of kids again approached him and accused him of calling 911, demanding to see his phone and its call log.

"I showed them my call log," he said. "That's how I got out of there."

Going public

The man went to work and, the next morning, instead of going to bed he decided to go public with the video of the attack.

"I wanted the public to know about it," he said.

"I've seen this firsthand. These kids harassed me. If I didn't do this, no one would have known about it."

Halcrow came out of the assault with bruises to her arms, legs and back. She reported the assault to police, and they say they're investigating.

Police confirm that they are also looking into reports of similar assaults in Pleasant Hill Park.