This is how they caught the girl stalker.

 An elusive hacker humiliated a group of high school girls. They joined a police investigator with a lot of determination to set a digital trap for it.

BELMONT, NEW Hampshire (7,200 inhabitants) is an old industrial town in the northeastern United States surrounded by lakes and forests. A hardware store and a hairdresser are all that the main street has to offer. At the local police headquarters, there is a box full of bills and bills that the neighbors have donated to support Vito, the boss's dog. "We don't have many people swimming in abundance," says Raechel Molton. For a long time, Molton, 42, was the only police investigator in the city. He grew up about 35 km away, in Concord. She was a bold girl who resolutely approached the uniformed police officers to ask them what they were wearing on their belts. When he was in fifth grade, an officer went to his school to conduct a drug awareness course. That's when he decided that he was going to be a policeman. In high school, Molton enrolled in a law and law-keeping course, during which she was assigned to travel in a patrol car with an officer. He told her that women should not become police officers. That did nothing but consolidate his ambition. In 2005, he joined the Belmont police. "This job catches you," she says, sitting with her back straight at the police headquarters and with her brown hair tied up in a tight bun.

Crime in Belmont is concentrated in the use of opioids, theft and theft. But shortly after, Molton found himself collecting complaints from parents and staff at Belmont High School about some teenagers who sent nude photos of him, often to the people they were dating. Emulating the officer who inspired her when she was a fifth grader, Molton gave workshops in high school on how to behave safely on the Internet. He warned the students that the photos of their nudes could be sent to certain unwanted viewers or uploaded to the network. The results were not what he expected.

"A girl told me: "What I learned in your class is that nothing happens as long as my face doesn't appear in the photo," Molton recalls. In the spring of 2012, after Molton was promoted to police investigator, a student entered the police station and said that someone she did not know and who was called Seth Williams had been sending her messages and harassing her to send her photos of her naked. Since she didn't want to send him any, she managed to enter her mobile phone account, she didn't know how, where she found some photos of her naked. Then he copied them and sent them to his friends. Hoping that Seth would leave her alone, the girl gave in and sent her an explicit photo. But he didn't stop. A few weeks later, another girl from Belmont high school appeared at the police station. A guy was harassing her too. Then more girls arrived. Some were embarrassed, others came in crying, and others arrived accompanied by their furious parents. Molton was facing a real epidemic. In 2011, MAY was a 16-year-old student at Belmont High School when her family moved to a nearby city and enrolled in a new school. "It wasn't very popular, we could say," May said. So when he received a Facebook friend request from someone named Seth Williams, with a beautiful profile picture, he accepted it. They exchanged numbers, and the sending of text messages began.She said nice things and seemed to want to meet her. He asked her about her favorite ice cream flavor and her pets.

When she asked for photos of her body, she hesitated. "I kept thinking that no boy showed so much interest in me," he said. "He actually looks like a nice guy. Maybe it's okay." May sent him a photo that she thought was funny, of her ass in jeans, full of handprints of her freshly painted room. Seth wanted more. Then he sent her a photo in underwear and then another naked one from the waist down. When he demanded a complete nude, he said: "No. That's where I draw the line." "There is no photo, there is no Facebook," he replied. When May tried to log in to his accounts, he could not access them: Seth had hacked his account and email and changed the passwords. He asked him to return the bills; he refused. He blocked it on his phone; he sent him a text message from a different number. She changed her number; even so, she found her. "I always came back," he said. "Always." One night in the fall of 2012, a text message rang on his phone. It was Seth, again demanding photos. This time, the text included nude photos of other girls. May recognized a friend of her days in Belmont. She called her friend, who urged her to talk to her mother and go to police investigator Molton in Belmont. "I remember taking a deep breath and going up the stairs. I sat on my mother's bed, and I told her, "Mom, I have something to tell you, and I don't know how," says May. The next day, May and her mother went to the Belmont police station. May met with Molton, who spent more and more time trying to solve the case. Seth had sent nude photos to other girls, too, and with his help, Molton was able to track down a dozen victims and discover a common feature: they had all attended, at some point, Belmont High School. I knew that some of the girls were suffering a lot. One began to sleep in the same bed as her mother. Several feared that Seth would attack them. A girl cried at night until she fell asleep. Another called her mother to work every day, crying, terrified of being alone. They fought against depression, anxiety, nausea. Molton spoke to the cybercrime unit of New Hampshire but was confirmed that there was no known stalker who followed Seth's pattern. Then he confiscated a girl's phone to try to get information from Seth, suggesting that he meet at a teenage club called Los Arches. He didn't seem to recognize the name, and she asked him if he was a neighbor of the area. In response to a summons, the TextFree messaging service sent information that identified Seth's phone. With that, Molton was able to request the registration and billing information of the phone. The results pointed to Ryan Vallee, a 19-year-old graduate of Belmont High School, a class of 2012. Molton needed more evidence to know if it was really Vallee. But he told some of the girls that he was the suspect, hoping to be able to alleviate their fears. "They really had the feeling that it was a monster," Molton said. "When they found out who he was, some of them reacted as, "Really?"

If they could classify him in any way, the classmates remembered him as a quiet and strange boy. A girl sat with him at lunch from time to time. I had even told him about his Internet stalker. Vallee had offered him his help to unmask "Seth." May knew Vallee from the school bus and had made an effort to be kind to him. What could I do to make him think I deserved this? He wondered. While Molton was trying to gather more information, he was witnessing another problem. Even if he could find evidence to arrest Vallee, the most he could accuse him of harassment, a misdemeanor that entailed a sentence of less than a year. "For a couple of those girls, it became their worst nightmare for a year and a half," he says. "I thought that the laws of this state were insufficient for that kind of fear." So Molton contacted the federal authorities. In October 2013, the federals learned that one of the victims had been about to commit suicide and accused Vallee of extortion. However, in a short period of time, they dismissed the case, opting instead to gather more evidence with the aim of arresting him again with firmer charges. Five months after the federal authorities took over the case, a new expert took office: Mona Sedky, a lawyer from the Department of Justice specializing in computer crimes and computer piracy.

A few years earlier, she had been called to help in a case against a man who had threatened to spread naked images of a young mother on the Internet. The man pleaded guilty, but shortly after his sentence, the victim committed suicide. Then Sedky found out that someone from his own extended family had experienced something similar at the age of 14. "I can't go back on your case, but I can help get other women not to go through the same thing," she says. Since then, Sedky has worked on a dozen cases of "sextortion." Although sextortion is not a federal crime, prosecutors can accuse people of fraud and computer abuse. Most states have outlawed the non-consensual exchange of sexual images, but it generally entails much milder sentences than the federal laws that Sedky trusts.

Matthew O'Neill, a Secret Service agent in New Hampshire, contacted Sedky for help with the Vallee case. (The Secret Service investigates computer crimes and identity theft.) Sedky became fully involved, issuing citations to Amazon, Skype, Yahoo, Google, Facebook, and others. He was finding the trace left by Internet users: the IP addresses of the registry, the dates and times, and the information of the registry. The researchers then went one step further, and went to the Internet providers to find information about the subscriber and its location. With these details in hand, O'Neill and other agents mapped the locations from where Seth had logged in. They all had a plausible link with Vallee: a restaurant near her mother's house, an air conditioning business belonging to her mother's ex-boyfriend. The Wi-Fi of a random person in Gilford, New Hampshire, turned out to belong to his sister's neighbor. These were crucial fragments of circumstantial evidence, and the researchers needed as many as possible. "In these cybernetic cases, the SODDI (Some other dude dit it) defense must be defeated," says O'Neill. When studying exchanges, O'Neill deciphered the way Seth accessed the stories of his victims. When Seth had conversations with the girls to become a friend, like when he asked May what her favorite ice cream flavor was and the names of her pets, she was really picking up clues that she would then use to answer the security questions of her accounts. Finally, in 2016, federal prosecutors had enough evidence to accuse Vallee of interstate threats, aggravating identity theft and fraud and computer abuse. The formal accusation listed ten anonymous women who had been convinced to appear. Vallee was released on bail and was ordered not to use the Internet. Although the evidence was solid, Sedky was worried; he knew from experience that putting vulnerable victims in the position of witnesses in court could be enormously distressing, "So they offered us incentives to try to get him to plead guilty to avoid a trial." But Vallee was inflexible saying that it had not been him, that someone else would have done it. AFTER GRADUATING from Belmont High School in 2011, Mackenzie moved to North Carolina. His mother had forbidden him to use social media in high school, so "he went a little crazy," she says. When Seth contacted her, he replied. But then Seth took control of several of his accounts and demanded a photo of his breasts. "I'm not going to send you any. You won't threaten me," Mackenzie wrote to him. Mackenzie, who says he was an abuser when he was younger, was determined not to cower. He printed his exchanges with Seth and took them to the police of his town. The police told him that he couldn't do anything. A year later, in 2013, Seth began using the pirated Facebook page of a student from Belmont to harass Mackenzie. Mackenzie sent a message to the girl, who told her about police investigator Molton. Mackenzie gave him dates and screenshots, to continue swelling the already extensive file. When the prosecutor's team called Mackenzie, she told them that Seth had stopped bothering her for a while, but that in recent months he had contacted her again, using the same hacked Facebook page of the Belmont student, identified in the court papers as M.M. This information was essential: it meant that Vallee was back on the Internet, breaking the terms of her bail. If agents could catch it with any device you were using, they would have your browsing and messaging history. With such solid tests, they could avoid Vallee's SODDI defense.

The government received an order requiring Facebook to deliver daily reports of the IP addresses and login times of M.M.'s Facebook Page. Meanwhile, Secret Service agent O'Neill took over Mackenzie's Facebook account. Copying the jargon of instant messaging he had learned from his teenage daughters, O'Neill posed as Mackenzie on Facebook Messenger. Alternatively, he flirted, flirted in the crazy way that "Seth" did, who, according to Facebook reports, accessed the application from a mobile phone. The investigators were determined to catch him. On a windy March morning, Secret Service agents parked their black SUVs next to Vallee's mother's house and her sister's apartment. They imagined that Vallee was staying in one of them. O'Neill, posing as Mackenzie once again, used Facebook Messenger to contact the hacker of M.M.'s Facebook page.

Just after O'Neill entered Facebook, Vallee left his sister's apartment. Secret service agents followed him. When he stopped at a traffic light, the officers jumped out of their SUVs, wielding the weapons. Vallee shot out, zigzagging in traffic. The Secret Service and the local police followed him to a dead end. When he got out of the car, a police officer yelled at him to throw himself on the ground. There was a backpack in the car. There was a phone inside the backpack. Five months later, Vallee pleaded guilty to 31 charges, including aggravating identity theft, hacking and cyberbullying.

A judge sentenced Vallee to eight years in prison. "It should serve as a warning to other people that this cannot be done," said Federal Prosecutor's Assistant Arnie Huftalen. "This is a real crime. It really harms people and causes wounds that will last a lifetime."