After a video of a violent assault against her 13-year-old son was shared on social media, a London mother took to Facebook to warn other parents.

CBC News has decided not to identify the woman because it might also identify the youths in the video, who are all minors.

The video shows her son being punched repeatedly by another boy. It was shared on social media accounts of youths in the victim's peer group, including some who attend the same east London elementary school.

The 40-second video shows the woman's son walking along a sidewalk as two boys follow and shout at him.

The video shows one boy repeatedly punching another multiple times. It was shared on social media among students of an east London school. (Submitted)

One boy in a black shirt tries to catch up with the woman's son while accusing him of pulling a knife. The woman's son denies it.

"Now you're in for a real treat b--ch," the boy in the black shirt can be heard saying on the video.

Video posted on Snapchat

The woman's son is then confronted, and struck in the face. He tries to walk away but is soon stopped again by the same boy and punched multiple times in the face and abdomen. He's also kicked once before fleeing at the end of the video.

The video was posted as a Snapchat story just after 6:30 p.m. on Wednesday, May 8, the same day the incident happened.

Although the Snapchat story expired after 24 hours, the video was copied and shared among students on other social media platforms, including Facebook. The father of the boy seen being beaten says he was alerted by a co-worker, who saw it on Facebook.

The boy's mother says a group of youth has been causing problems for her son "for the past few months at school."

The boy's mother has spoken to police and the school principal about the incident.

"Seeing my son get hit over and over and not being able to help him is KILLING me! - Mother of victim

"The school just keeps telling me to call police, but the police can't do much because these children, a lot of them are underage," she said.

CBC News asked London Police Service spokesperson Const. Sandasha Bough about the incident.

She wouldn't say whether or not charges were laid, saying that doing so could identify people in the video.

"Officers were made aware of this situation and investigated the incident on May 9," said Bough.

Bough said she can't comment further because the incident involves minors who can't be identified under the Youth Criminal Justice Act.

The boy's mother says it's not the first time videos of assaults have been carried out and shared among kids in her son's peer group.

"They tape this stuff and think it's funny, so they're doing it for fun basically," she said.

Mother's Facebook post prompted threats

Last week she posted on Facebook about the assault in a bid to warn other parents.

"I haven't been able to sleep or eat," she wrote. "Seeing my son get hit over and over and not being able to help him is KILLING me ! So before this happens to anyone else I am trying to get the word out."

Her post also offered to share the names of the youths involved in the incident with any parent who contacted her.

That Facebook post had more than 1,100 shares and 160 comments before it was pulled down late last week.

Some parents thanked the woman for posting the video. Others shared their own stories about having their kids being bullied and assaulted. But her post also prompted threats, including this one in which the person making the threat identifies themselves:

And this one:

The mother of the boy beaten in the video says she's shocked by the brazen nature of the threats.

"I honestly didn't think that these children were going to take it to this level," she said.

The woman says her son has stayed home since the incident captured in the video.

CBC contacted the Thames Valley District School Board about the incident but had not received a call back by Friday.