Barton Scott found the girl on Snapchat. He pretended to be her friend and persuaded her to give up her password. Then Scott took what he really wanted: The photos marked "My Eyes Only."

Scott, in his mid-30s at the time, used the girl's risqué images as leverage, threatening to publish them online if she didn't do what he wanted.

He wanted more graphic photos. He wanted videos. She sent them, fearing that her life would be over if he made good on the threat. She was 15 years old.

About five years ago, the U.S. Attorney's Office in Minnesota first started seeing "sextortion" schemes like this one, in which predators target young people online. Prosecutors say they've since seen an alarming rise in frequency of these devastating and hard-to-solve cases.

"It doesn't matter where a kid is from — their economic status, social status — it seems to touch every group of kids that's online," said Miranda Dugi, an assistant U.S. attorney in Minnesota.

The term describes a range of online crimes involving coercion, usually on social media sites or apps. A predator often poses as a teenager and manipulates a victim into sending sexually explicit photos. Some, like Scott, pretend to be a friend or acquaintance. Others use a fake photo and online profile and strike up an online romance.

Then they prey on the child's worst fear — to be exposed to their classmates, coaches, teachers or faith leaders — unless their victims give money, photos or sexual favors.

With the boundless reach of the web, perpetrators can engage in hundreds of scams with different victims. One case in Minnesota involved a National Guardsman preying on children from Afghanistan.

Scott, who lived in New Richmond, Wis., and worked in Minnesota, was sentenced to 25 years in prison last month. Prosecutors in that case say they believe he ensnared hundreds of victims, from Maryland to Colorado. Many of them may not even know Scott has been imprisoned, as victims were never identified.

And that's the horror of this crime, says Dugi: "A single person sitting in a single location using a handful of accounts can just wreak havoc all over the country."

Because sextortion is a relatively new development in sexual cyber crime, it's hard to say exactly how often it happens and who is targeted.

One recent report, conducted by the FBI's internet Crime Complaint Center — known as the I3 — found a 242% increase in cyber extortion crimes from 2017 to 2018. That jump includes a variety of online schemes, but the report noted that the majority were "part of a sextortion campaign in which victims received an e-mail threatening to send a pornographic video of them or other compromising information to family, friends, co-workers, or social network contacts if a ransom was not paid."

"It's a new frontier," said David Finkelhor, director of the of the Crimes against Children Research Center at the University of New Hampshire. Finkelhor said most cases fall into one of two categories: a romantic relationship ends and one of the parties coerces the other with private images, or a stranger targets and manipulates the other person online. Both are difficult to police, especially for young people who see it as normal to take and share nude photos.

"You will hear people say things like, 'We should tell kids, don't ever make sexy pictures of yourself and send them to someone,' " Finkelhor said. "But we don't really know how to handle this problem."

Sextortion isn't specific to minors. Jeff Bezos, Amazon's 55-year-old chief executive, claimed in February that the National Enquirer targeted him with a sextortion scheme, threatening to publish a cache of embarrassing photos, including a "below-the-belt selfie."

Ohio-based attorney Nadeen Hayden said she's seen a spike in adult male clients being extorted by women they've met on adult websites. "It's a modern nuance of when a relationship goes bad, added to these relationships where people barely even know each other," she said.

But 71% of sextortion victims are under 18, according to the Brookings Institution, a nonprofit that conducted the one of the first studies quantifying sextortion in 2016.

The crime also isn't gender specific. Last year, a judge sentenced Marcus Hinkle, a former YMCA worker from Burnsville, to 20 years in prison for targeting 13-year-old boys on X-Box and Instagram. This method of online trickery is most common among minors, according to the Brookings report, which concluded 91% of juveniles were manipulated through social media scams.

The report also found perpetrators get a much lighter sentence if the case is prosecuted locally instead of federally. It concluded that Congress had failed to adequately address this new evolution of cyber crime against children, and that the emerging threat of sextortion was so prominent they should create a new law to better punish perpetrators.

Perhaps the most devastating case of sextortion to ever hit the Midwest began in Eagan.

On Oct. 2, 2015, federal agents and Minneapolis police officers raided the single-family home, located near an elementary school, where Anton Martynenko lived. They found flash drives and tablets in the ceiling and walls containing thousands of photos of boys and young men, sorted meticulously by the victim's name, age and hometown.

Using fake photos of young girls, Martynenko targeted boys in several states on Twitter, Facebook and Instagram. Telling them he was a student at the University of Minnesota or new to the state and trying to make friends, Martynenko tricked the boys into sending him naked photos. He told some he was a modeling agent, even mocked up fake contracts. When the boys stopped responding, Martynenko splashed their photos on social media.

In 2016, Martynenko was sentenced to 38 years in prison in what federal prosecutors called the biggest child pornography case ever in Minnesota. Investigators believe his sextortion scheme reached 150 to 300 victims, according to court records.

At least two of those have since killed themselves.

Kate Buzicky, the assistant U.S. Attorney who prosecuted Barton Scott, said the element of control seems to be the draw for some perpetrators. In the Scott case, "it reminded me of a cat with a baby animal, just batting the victim around and trying to make that person feel humiliated and worthless and scared," she said.

The power of pending humiliation makes it harder to police, because it makes the victims less likely to tell their parents or an authority figure.

Minnesota doesn't have a law specific to sextortion. However, in 2016, lawmakers cracked down on revenge porn, making it illegal to share images without consent from the subject.

Andy Mannix • 612-673-4036