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TACOMA -- Kelsey Fischer has taught hundreds of Pierce County high school students how to recognize unhealthy relationships in a digital age.

“It’s more common than we realize,” said Fisher, who shares in every presentation that one in three U.S. adolescents has been a victim of physical, sexual, emotional or verbal abuse from a dating partner. "I point that out to let teens know the magnitude of it. They think teen dating violence has to include physical abuse."

But the YWCA youth advocate doesn't need a national statistic to prove her point.

The proof is on a list Fischer keeps, with names and numbers of more than 50 Washington students who've asked for her help since she started speaking in local health classes last September.

"A good chunk of them will call because they are worried about a friend," she said. "Usually, when they want to talk it's because of something physically happening or they have questions like, 'Does this count as abuse?'"

Kelsey Fischer (Provided Photo)

That's sometimes a tricky question for Fischer to answer. Because while teen dating violence is an age-old problem, social media and technology have changed what it looks like in 2017.

READ MORE: Dating Abuse Statistics

"Cell phones are really playing a large part in how teens experience that pattern of control," said Jennine Devenuti, education and prevention manager at YWCA Pierce County.

It's common, youth advocates say, for the technology to create a lack of trust between partners, leading to unhealthy dating habits and potential abuse.

"The partner may be under surveillance, if you will. If one partner says 'Hey, I'm at home with my mom,' the other partner may say 'Send me a picture right now. Check in. Let me know where you are.'"

Experts call it digital control -- those relationships where one partner demands passwords, reads text messages and expects constant contact with their significant other.

"While the technology has changed, the dynamics haven't. There didn't use to be Snapchat or Instagram, but people were still finding a way to check up on each other to have control," said Ilene Stohl, program coordinator at the Washington State Coalition Against Domestic Violence.

A Textbook Scenario

Last December, one of Fischer's lectures at a Tacoma high school caught the attention of a 17-year-old girl in the second row.

"She was already concerned, and then hearing the information from the presentation really confirmed it. She wanted to talk after class," Fischer said. She declined to name the teen due to confidentiality concerns.

The student was worried about her friend, who was dating a male student at the same school. She told Fischer that her friend felt significant pressure to immediately respond to her boyfriend's texts.

That's a red flag for experts who work with victims of teen dating violence.

"I hear a lot from young people that there's this pressure to be instantly responsive because the consequences for not being responsive are pretty big," Stohl said.

But it wasn't just the texts that had the 17-year-old friend on watch.

"She noticed that (the boyfriend) checked in on her friend a lot," Fischer said. "(The boyfriend) wouldn't even let (his girlfriend) leave the classroom because he was worried that a guy would try to get with her in the brief time she would get a pass to go to the bathroom," Fischer said.

"It was a textbook scenario of an unhealthy relationship."

A Blurry Line

Sometimes, the line between normalcy and unhealthy behavior is much more difficult to draw -- especially in an age when both nonstop texting and 24/7 responses are standard among young people and many adults.

"A lot of teens will push back on that and say 'They check my phone, but I check theirs, too.' We talk about being honest with yourself and ask 'Are you absolutely OK with them checking your phone?'" Fischer said. "I think for some teens, it really can just be something common that they do, and not necessarily unhealthy."

To Betsey Archambault, executive director of the Vashon DOVE Project, incessant texting can be a form of abuse.

"We have seen people that have come in here and they're like 'My boyfriend texted me 100 times in the past hour.' That's pretty full on. That's not 'Hey, how are you doing?' That's 'What are you doing? Who are you doing it with? When you are leaving? When can I see you?'" she said.

But even when the line of abuse is clear to friends and family, experts say teenage victims in unhealthy relationships often can't see there's a problem.

“I think they sometimes see it as romantic and say 'Wow, this person really loves me because they want all my attention and want me to focus only on them,"' Fischer said.

Tracking Locations

Some teenagers will go to great lengths to track their significant other's location, according to domestic violence experts who've watched the tactics unfold.

"There's a lot of hacking into people's accounts to read what they are writing to their friends, and to find out who they are with and what they are doing," Archambault said.

She said teens in unhealthy relationships sometimes sign into mobile GPS trackers, too.

They use apps like "Find My iPhone" and "Find My Friends" to trace their girlfriend or boyfriend's phone. They also monitor their partner's social media profiles to see exactly when and where they "check in."

"It's a common and a fun thing for people to say (online): 'I'm here having a milkshake.' But that also lets the person who is stalking you or abusing you know exactly where you are," she said.

Stock photo.

Lessons For Parents

Experts say it's important for parents to take note of any unusual behaviors involving their teenagers, their relationships and their digital devices.

"Let's say you're having dinner with the family and the teen will not put down the phone and the parent is like 'Look, we're having dinner. Put your phone away,' and they get upset about it. (Understand that) there may be a consequence if they don't answer that text," Devenuti said.

But while it may be tempting to worry, she cautioned parents to not jump to conclusions without looking at the whole picture.

"Just because a parent sees their teen or their partner saying 'Hey, who are you with?' doesn't necessarily mean the relationship is abusive," she said.

"The thing to look out for is who's life is being diminished? Has one partner stopped playing sports? Has one partner stopped hanging out with friends? It's looking at who's life is getting smaller and who's life is getting bigger."

Archambault encouraged parents to proactively listen to how social media is impacting their teen's every day life, and then have a discussion about healthy romantic relationships.

"In our culture, we absolutely talk about the unhealthy behaviors. Everyone knows that physical abuse is bad. But what's the flip side of that? What does an actual healthy relationship look like?" she said.

As for Fischer, she said she's focused on helping teenagers learn how to recognize and stop their own unhealthy dating habits because they may not even be aware of them.

"I'm really careful not to call the person doing an unhealthy behavior an 'abuser,' because it doesn't mean this is how you are forever," Fischer said. "Young people, a lot of times, only know how to be in a relationship because of examples in their own lives."

This story is a local addition to our national series, "If My Parents Only Knew," which helps parents understand the tough issues teens experience and their social media secrets.