More than 460 charges have been laid against 34 teens who were using Edmonton's LRT system to carry out a months-long crime spree which included kicking a woman down the stairs at a transit station in a random attack.

"Officers have responded to close to 90 criminal events involving 66 complainants, some of whom are now dealing with very serious internal and facial injuries," Edmonton police Supt. Tom Pallas said Wednesday.

While two of the young people charged are 18 years old, the others are between 13 and 17.

Surveillance video shows two attacks at LRT stations in Edmonton, part of a year-long crime by dozens of teens. 0:39

The crimes, which happened between January 2017 and March 2018, included personal robberies, thefts and mischief incidents, all committed by groups of young people.

The teens face a long list of charges including aggravated assault, robbery, weapons offences, credit card fraud, shoplifting, mischief and possession of a controlled substance.

"I'm hoping this is a wake-up call to all of these teens that were involved in this," Pallas said. "If you're going to show such contempt and disrespect for our community and the law, you'll be held to account for these actions."

During a news conference Wednesday, police released some of the surveillance footage gathered during their investigation.

One of the videos, from Jan. 14, 2018, shows the violent attack on a woman at the Belvedere LRT Station.

The woman can be seen stepping into view of the security camera before she is kicked in the back and falls face-first down the stairs, suffering serious injuries.

Another video shows what police describe as a "swarming" incident. Two teens used social media to create a flash mob at the Century Park LRT station, leading up to the attack on two male teens, Pallas said.

"People show up and then it's just a mass of people running around the area, kind of a mob mentality," he said.

One of the victims was taken to hospital with serious injuries following the assault. The two suspects have since been charged with assault causing bodily harm.

Investigators believe 12 of the 34 individuals are prolific offenders who were involved in a majority of the incidents.

"Many of these individuals have been arrested, gone through the court system and re-arrested by our officers after being released on bail, in some cases within hours," Pallas said.

Some of the suspects were students who attended a variety of schools, he said.

The crimes were reported at Belvedere, Southgate and Century Park LRT stations, at convenience and grocery stores, and the Clareview, Terwillegar and Saville recreation centres.

'The system is safe'

Mayor Don Iveson was shocked to see the video, but is glad that there is video of the "awful behaviour" in the first place.

"The footage itself is part of, I understand, what has helped to apprehend the people responsible for this," he said. "So people, at least, can be reassured that there are eyes on the system at all times, and that creates accountability."

The mayor said the 120,000 people who ride the LRT every day are safe, and these violent incidents are the exception.

"In this case, the cameras worked, the system worked, the police did their jobs, and so far people have been, so far at least, apprehended and hopefully held to account.

"Overall the system is safe."

City council has increased resources to peace and police officers since a 2015 pilot project. Iveson said time will tell if more support is necessary, adding that crime trends are monitored to determine how resources are allotted.

"All we've seen today is that the people were caught. That shows that the system works," he said. "And, again, we'll look for advice from our security experts and the police on whether changes are needed, in terms of personnel or more cameras."

Frightened and flabbergasted

Matthew Stepanic takes the LRT two to three times a week and, after watching the security video, feels uneasy about riding the train.

"I'm a little bit flabbergasted that something like that would occur," he said.

Stepanic said raising awareness and increasing police presence in isolated areas might help prevent situations like this. It won't deter him from taking the LRT, but he'll be more aware of his surroundings.

"I'll be more watchful when I'm actually on the train and probably looking twice at people who are around," he said.

Jorden Umpherville, 24, takes the LRT three times a week to her classes at MacEwan University. She was shocked at the video's violence.

"Why would you ever do that? That's horrible!

"It makes me really upset and I want to know who the hell did that," she said.

Umpherville said there are ways to protect yourself when using the LRT system.

"Watch out what stations you're using, what time you're using it at," she said. "Make sure people know where you are in case you do pass out or something really bad happens. And just be aware."

City council should create new policies with police, Umpherville added.

"I haven't seen very many officers at the LRT stations myself, but I know that they are there at some point. Maybe [the city] could increase that as well."

Warren Uhrich and Amanda Steinkey both say it's not surprising to see this kind of behaviour throughout Edmonton's LRT system. (Trevor Wilson/CBC)

Amanda Steinkey has been taking the LRT for the past four years.

"That's kind of frightening actually to see that that's happening on public transit, because we take public transit to be safe and as an alternative to driving," she said.

Steinkey said an awareness campaign and more officers on patrol would make a difference.

"I definitely have seen stuff that's questionable on the LRT, and drivers don't do anything, other passengers won't say anything," she said. "So I think we need to have the right people in place to help out with that."

Warren Uhrich said it's hard to be surprised.

"I don't think there's a lot you can do to prevent that, as unsettling as it is that that can occur," he said, though he added a stronger security presence could be a deterrant.

Diana Bull said she hopes the woman in the video is OK.

"That's so disrespectful," she said. "And they need more security then. Everywhere."