In its early days, around 2006, Anonymous was about the “lulz,” or the laughs, often crass pranks that were directed at anyone who set the group off. But in the past five years, the group has become increasingly politicized, coalescing at first around the defense of free speech and an uncensored Internet. In the last year or so, Anonymous has taken on what’s called “white knight work,” which has mostly involved coming to the aid of girls who say they were the victims of sexual assault that the police failed to address. White-knight ops aren’t about Internet freedoms, but they are in keeping with the Anonymous ethos of distrusting and challenging mainstream authority. “When you see a convergence of scumbaggery and the sense that the police are not doing their jobs, along with hypocrisy and corruption, that definitely interests Anonymous,” says Gabriella Coleman, an anthropologist at McGill University who is working on a book about the group. As one veteran Anon called Crypt0nymous told me, “People have to bring justice in the name of the law if the government does not do it.”

Anons tend to see the cases in which they intervene in polarized terms, parables with an innocent victim, evil perpetrators and ineffectual (or corrupt) law enforcement. There have been notable instances in which the pressure they created from a distance brought needed scrutiny to a case that had otherwise been ignored or buried. But because these activists have no local roots, they can also be blind to important subtleties and wind up falsely accusing or demonizing innocent people. Whether an op does good or ill depends entirely on the care of the people who sign on, because there are no built-in checks, no authority figure who can call off Anonymous.

On the day in April when Ash first learned about Rehtaeh Parsons, he spent his lunch break sending messages about the case to several OpAnti­Bully members. The group quickly agreed that the first goal was to figure out who the boys were. Members of the team started looking for clues on social media.

Ash had to go back to his day job, but, he said, “every spare moment I had I would check my accounts and see how everything was coming together.” At day’s end he rushed to the bus stop for his hourlong commute, arriving at the home he shared with his girlfriend of nine years and then spending the rest of the evening working on tracking down the boys’ identities. “For nothing to happen to the boys who did that to Rehtaeh, . . .” Ash said. “We wanted to strike fear into their hearts.”

Last summer, I waited for Ash at a bus stop in south London. We had been emailing for months, but this would be the first time I met him in person. I stood at our appointed spot until a tall guy with a fair complexion approached me. He wore a black T-shirt and carried a frayed backpack. He told me his age and asked if I had expected someone older, though I hadn’t.

We walked to a shady courtyard by the Thames for lunch. Ash has a nervous habit of cracking his knuckles. A tattoo on the back of one arm reads, in looping cursive, “I swear I’ll never give in or refuse.” In high school, he said, he hacked into his online yearbook and turned some of the entries about individual students into jokes. “I changed loads of them,” he said with a grin. The stunt got him kicked out of his classes for business and I.T., Ash said, and he was told he “had no future.” Instead of university, he went to night school to learn engineering. His work was steady but he found it dull; it’s his activist life that consumes him and feels full of promise and opportunity. “It’s hard for me to turn off my laptop at night,” he said, acknowledging that this was a source of tension between him and his girlfriend. When the three of us ate dinner together, she made clear that she had no desire to talk about OpAntiBully. And yet that was the subject that made Ash light up. His dream, he said, was to apply for a grant to start a website devoted to white-knight work. “If I could quit my job and do this all day long, 10 hours a day, the effect and the fulfillment would be massive,” he said.

If Ash’s girlfriend didn’t appreciate this, his fellow OpAntiBully members did. I talked to Ash and Katherine together over Skype soon after they started OpAntiBully. They were like a couple in the honeymoon phase of a relationship, finishing each other’s sentences and insisting that it didn’t matter that they had never met in the real world. “It gets to a point where the realism of someone — what they look like, what they do for a living — is secondary,” Ash said. “You really get to know people online. If anything, they share more.”