Most stories about human trafficking that make it into the headlines in Canada involve women from other countries being brought here and forced into sex work, but those who work with trafficking victims in this country say the majority are, in fact, Canadian-born teenage girls.

Vanessa, 18, is one of them. She was a typical high school student in Mississauga, a city just west of Toronto, until two years ago, when she fell in with a new boy who enrolled at her school.

"Right from the beginning, he knew ... I was the one that was, I guess, vulnerable," said Vanessa, who is using a pseudonym to protect her identity.

He always kinda told me what to do, and I would do it. - Vanessa, 18, human trafficking victim

"I'm very kind of submissive to people. He always kinda told me what to do, and I would do it."

One day, a car showed up with two men in it whom she didn't know. Her friend asked her to get in, and she did.

"I was still in my school uniform," she said.

As they drove to a motel on a strip of Dundas Street East in Mississauga, one of the men told her she could make a lot of money doing sex work. Vanessa said she was unsure and scared but felt pressured to go along with it because the two men were friends of the boy she knew.

"At that time, I didn't try to understand what was going on," she said. "My friend promised me all these things that I felt that I needed — a stable place, money in my hands. It was kind of part of me wanting to do it and see if I could get something better, and then a bigger part was that I was already there and I can't really say no anymore."

Most trafficking victims are Canadian

Peel Regional Police say 60 per cent of all reported human trafficking cases in Canada occur in the densely populated Greater Toronto Area.

Girls are recruited in various ways — at school, on Instagram, at the mall. Most continue to live at home while carrying out sex work at local motels or condominiums.

According to police, human trafficking doesn't have to involve the crossing of a border. Any forced recruitment, confinement or transportation of a person for the purposes of exploitation falls under the Criminal Code definition of trafficking. Trafficking for sexual exploitation is just one form of the crime. Others include forced labour and domestic servitude.

A Peel Regional Police poster targeting victims of sex trafficking. (Peel Regional Police)

More than 90 per cent of the victims of sex trafficking within Canada come from Canada, according to government statistics,

Vanessa's story is typical, says Jennifer Keeler, a nurse practitioner at Chantel's Place, a sexual assault support centre in Mississauga.

"Human trafficking targets young adolescents trying to fit in," Keeler says. "They are vulnerable to someone giving them attention."

You have these guys making regular girls feel special, buying them things and taking them shopping … [They] know exactly how to build dependence. - Katarina MacLeod , former trafficking victim

Traffickers know exactly what to say to manipulate girls, says Katarina MacLeod, a former prostitute and trafficking victim from the same area as Vanessa.

They're even targeting girls not usually considered high risk.

"You have these guys making regular girls feel special, buying them things and taking them shopping," MacLeod said. "And the girls fall for it hook, line and sinker … [The men] know exactly how to build dependence."

MacLeod said traffickers are targeting young and younger girls these days.

"Girls as young as 13 are getting recruited in," she said.

'He didn't smell nice'

The men who took Vanessa to the motel first took photos of her to use in ads for her services. They gave her a cellphone and told her to use it to negotiate with her first client as they watched. She settled on $40 for five minutes of unspecified sexual activity.

"He was older, probably in his late 40s … He wasn't dressed well. He didn't smell nice or anything," she said.

"I just kinda dealt with him because I thought five minutes wasn't anything. But now, I realized how stupid that was."

One of the men ordered Vanessa to turn over the money she made.

"He was like, 'I paid for the room so you have to give me everything,' so I just gave him all I made," she said.

The strip of Dundas Street East in Mississauga that houses the motels where Vanessa works with her pimp. Many underage trafficked girls work in this area. (Seema Marwaha)

Unlike sex workers who have chosen the trade, trafficking victims rarely get to keep the money they bring in. And they have little say over what sex acts they perform.

Peel Regional Police estimate a trafficked girl working daily can bring in up to $280,000 per year. For pimps who have multiple girls, the earnings are often divided among a team of traffickers, minus expenses for motels and the ads they take out to market the girls.

For months, Vanessa would get picked up from school almost every day and be taken to hotels on the Dundas East strip to have sex with clients arranged by her pimp. She was still living at home.

"My parents still somehow didn't know what I was doing," she said.

Vanessa met a network of pimps, recruiters and other high school girls like her.

"Most people have no idea something like this is happening in Mississauga," she said.

'Complex and hidden crime'

In 2015, Peel police made 39 arrests and laid 244 charges related to sex trafficking. In the first half of 2016, according to their most recent statistics, they made 25 arrests and laid 149 charges. As recently as last week, Toronto police arrested two young men in connection with the trafficking of two teenage girls at Mississauga motels.

And that's just a fraction of the problem, says Ontario's recently appointed anti-trafficking director, Jennifer Richardson.

"The number of how many people are actually being trafficked in Canada I don't think anyone could ever give you because it is such a complex and hidden crime," she said.

Hear Vanessa's story on CBC Radio's The World This Weekend, Sunday at 6 p.m. ET (7 p.m. AT, 7:30 p.m. NT).

Based on data she helped gather in Manitoba, she estimates the number of trafficking victims in Ontario alone to be in the thousands. A former trafficking victim herself, Richardson says victims don't come forward for a variety of reasons, including fear or a dependent relationship with their pimp.

Peel police keep so-called go bags on hand to give to victims of trafficking and assault. They contain toiletries, a change of clothes, public transit fare and gift cards. (Seema Marwaha)

Peel police established a Human Trafficking Service Providers Committee last year and have been working with local organizations to raise awareness and provide support to victims like Vanessa.

"The traffickers control the lives of the victims emotionally, psychologically and financially. Anyone can be a victim," said Const. Joy Brown, who heads up the committee.

A few of the red-flag behaviours to watch out for in young girls, she said include: extended periods when whereabouts are unknown; sudden changes in routine; having more than one cellphone; receiving expensive gifts; extreme tiredness and unexplained absences from school.

One of Vanessa's teachers recognized changes in her behaviour and connected her with a support program, which is how CBC News found her. Now, Vanessa is looking to get out.

"I hate doing what I do," she said. "I've been getting sick, my body is tired, my knees are hurting."

She says she won't come forward or testify against her pimp, who's now letting her keep some of the money she earns.

"I would feel like such a victim if I came out with no money. I want to have money to live comfortably. And then I plan to get out of it."