Mark de Rond is a Cambridge University professor – and a member of a group of vigilantes who livestream their “stings” on suspected child sex offenders. Are they doing more harm than good?
“That’s him, I’m sure of it,” says Lindsey, who belongs to Cobra, one of the UK’s most prolific paedophile hunting groups. It is a beautiful spring morning in rural Norfolk and their suspect, Nigel, has driven his family sedan 45 minutes east to meet a child at a roadside restaurant. For weeks he has been grooming somebody online whom he believes to be a 12-year-old girl, but is in fact a “decoy” – an adult volunteer from Cobra posing as a child. This is what Cobra do: they set traps for child predators – and Nigel is about to get the shock of a lifetime.
Cobra, short for Children Online Battling Real Abuse, is run by Jay, 6ft 2in and covered in tattoos, and his wife, Saz, who works as a “decoy”, both in their late forties. Jay, a factory foreman, says his life revolves around catching “wrong ’uns”. He funds the Cobra work himself. There is another man on the “sting” who might not appear to fit in with the others. He is in his fifties but has a boyish face, floppy blond hair, spectacles, a European accent and a studious manner tempered by an innate love of adventure.
Mark de Rond is a Cambridge University professor. His expertise is organisational ethnography, a branch of social science that studies and monitors human behaviour. He immerses himself in niche groups – previous subjects have included Boat Race crews, peace activists and medics in Afghanistan – to study their subculture and write books about them. He wanted to learn what makes paedophile hunting gangs tick, and so joined Cobra between 2018 and 2022. The group accepted him to bear witness to their work, giving him insider knowledge on how they operate and how they interact with the police and the child predators they hunt – which he reveals in his latest book, Dark Justice.
These groups are not law enforcement but are formed by members of the public, generally using Facebook. Some call them vigilantes; others see them as heroes protecting our children. De Rond, 57, joined Cobra in August 2018, finding himself in the company of factory workers, hospital porters, construction workers, a few ex-armed forces and the odd barrister, solicitor, journalist and stockbroker, though “white-collar workers seemed the exception”, he says.
De Rond went on 30 paedophile stings with the group. “I am a participant,” he tells me from his book-filled office at the bottom of his Cambridgeshire garden. “An observing participant. My job was to make a phone call to police after the predator had been confronted. That was my job. But sometimes you have to hold a camera to film a sting, for example. You’re part of the group and it’s not like you can say no. You tell yourself that the ends justify the means. The police can’t do the same work easily.”
The operation against Nigel stood out, as it was to have serious ethical and emotional consequences for the members of Cobra.
The Norfolk sting
It is 1pm on April 13, 2019. The group are in the restaurant car park, ready to pounce. Nigel (not his real name) is a “bad ’un, a monster and a slaphead nonce”, according to one Cobra member. In online chats with a decoy he has made comments about his granddaughter that suggest he may have abused her. “I will stab that f*** in the face if he has, I am not kidding,” Lindsey says.
They watch Nigel, a grandfather of eight in his sixties, park his car and light a cigarette before walking towards the diner. Then team Cobra pounce. Livestreamed on Facebook – to an audience of thousands – Nigel is marched to a private spot and shown evidence that he is willing to groom a 12-year-old. The usual excuses come out: he thought she was 18, despite being told the age of the child three times by the decoy. This is a normal rule used by Cobra and other teams to make sure the predator fully understands the proposition.
“You’ve f***ed my life up,” Nigel says.
“You’ve done that yourself,” Jay, Cobra’s leader, replies.
“Now I’m going to be arrested for being a paedophile,” Nigel says.
“That’s what you are,” Jay responds.
The police arrive and Nigel is arrested and held for two days before being released on bail. Just before his release Cobra receive an email from a member of Nigel’s family, begging them to remove the video. “Please, think of his wife, children and grandchildren … please, I’m begging you.”
Jay replies to the email saying, sorry, but the man was a serious predator.
A few days after the sting the group receive a second message, this time from someone close to the family. It carries shocking news: Nigel has taken his own life, just hours after being released on bail.
“I’m not berating you guys (you did us all a favour),” the message reads, “cuz one of the brothers would have done time if they had found out …”, implying a family member would have taken the law into their own hands against Nigel. “Thanks for all the hard work you guys do. And if you’re ever in the area again there would be a hot drink and a bacon buttie here.”
De Rond describes how some members of Cobra struggled with Nigel’s suicide, particularly Saz. When the professor asked her if she was OK, she replied: “Not really. Between us, I want to hunt no more. I feel shit someone killed themselves, although I know he done wrong, but now his family are left behind because of me. I’m scared if the next one I stand in front of does the same and I feel like I have blood on my hands.”
Others in the group were less sympathetic. Two hunters posted emojis of a dancing girl into Cobra’s private chat group following Nigel’s death, saying he was a monster so “who gives a f***?”
As for de Rond, who wasn’t holding the cameraphone during the sting on Nigel, he writes: “My own reaction to news of the suicide surprises me insofar that I don’t feel much of anything at all, except perhaps anticipation around how events will unfold from now on. How will Cobra respond to it?”
Saz continued with her work, feeling it was her duty to do so, along with her husband, to protect children. Cobra took down the sting video from Facebook out of respect for Nigel’s family.
But public humiliation and punishment are all part of the modus operandi of paedophile hunting groups, of which there are about 150 active in the UK today. Their methods are relatively simple. First there is the “set-up”, which involves a decoy going into the chat rooms of various social media platforms – Facebook, TikTok, Snapchat – pretending to be a child. The decoy will engage in chats with various individuals until they find one that engages in sexual communication with the child or sends them sexual material. De Rond was astonished at how easily this happens.
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“I sat with one of the hunters,” he says. “He went on a social media platform and created a profile for a girl of 15 years of age. In less than one minute he was approached. There were different men saying hello, sending pictures of themselves. It is disturbing how many men think it is OK.”
The decoy will then hand the chats over to a “hunter”, who will assess the material and decide whether there should be a “sting”, which will inevitably mean hunters tracking down that person, fronting them up with the chat room evidence and calling the police, while livestreaming the sting to tens of thousands of Facebook followers.
Why do the groups not simply hand over the chat room evidence to police? “There is a narrative,” de Rond explains. “The hunters’ journey has to end. The knight has to ride out and slay the dragon in front of the public. For them, the narrative is not complete without it.”
In this case the confrontation ended with suicide. Many people, including the emoji-posters in Cobra, would say, who cares? Nigel was a dangerous paedophile. Except the child was not real: it was a fictitious set-up created by Cobra. There was no judicial process or presumption of innocence. And Nigel is now dead.
A disturbing reality
De Rond grew up in a religiously conservative family as the eldest child of Dutch Christian missionaries on the island of Curacao, off the north coast of Venezuela. As a boy he would go with a Spanish guitar decorated with angels around local hospitals, where his family would sing to the patients. Financial hardships meant his father made all their furniture and he had one pair of shoes for church. Was it his upbringing that gave him an interest in niche groups?
“Possibly,” he smiles. His family left South America when he was seven and he grew up in the Netherlands, then later moved to the UK. He is married and has two daughters.
“It made working with Cobra even more sensitive for me,” he says. “I was disturbed by what men said they would do to kids – from the mild to the horrendous stuff. Some of the stuff police say they see, it makes your head spin.”
De Rond acknowledges that writing a book about paedophile hunting is an “icky” subject, dealing with issues difficult for society to face. His research throws up statistics that are horrifying to read.
UK police are given one new child abuse claim to investigate every seven minutes, while the National Crime Agency (NCA) estimates that 550,000 to 850,000 people pose a sexual threat to children in the UK. Together with the police, the NCA arrests, on average, 842 of them a month, while safeguarding 1092 children.
Social media and smartphones have provided predators with a way to groom children in the supposed safety of their bedrooms: WhatsApp, Facebook, Meet24, Jaumo, Snapchat, Kik and Grindr are the most popular of 65 platforms identified by police as having been used for grooming, de Rond says.

The template adopted by most paedophile hunting teams was set by To Catch a Predator, an infamous series of fly-on-the-wall reports on the American programme Dateline NBC, where adults from a hunting group called Perverted Justice pretended to be 13- or 14-year-olds online. The series ran for 12 episodes. Men were persuaded to travel long distances to meet the “child”, only for the show’s host, Chris Hansen, to appear with TV cameras. As the predator would try to escape, they were cuffed by cops and taken away. The final episode featured a sting on an assistant district attorney for Rockwall County in Texas, William Conradt. The reality TV show was pulled after Conradt took his own life.
One of the first known UK paedophile hunters was Keiron Parsons, who used the pseudonym Stinson Hunter. He was the subject of a 2014 Channel 4 documentary, The Paedophile Hunter, which won a Bafta.
Between April 2019 and March 2020 the number of hunter teams known to police grew to 191, and they confronted 1310 suspects. Since the pandemic the number of teams has dropped – between April 2022 and March 2023 there were 104, but the number of confrontations had risen to 1410, according to de Rond.
Cobra has a high turnover of members. “It’s not easy work to do,” de Rond explains. There is an emotional toll to hunting – late nights, busy weekends, long car journeys. “Decoying is the hardest. The decoys are mostly women. You have to be online all the time. You are absorbing all the vile stuff.”
Roughly one in seven stings takes place in London, with the West Midlands, Yorkshire and the Humber and the East Midlands not far behind. Nearly 41% of stings are “meets”, meaning that predators have agreed to meet their “child” in a public location, usually a train station, hotel, car park or fast-food outlet. The remaining 59% are “door knocks” where hunters have found out where a predator lives or works.
Tensions with law enforcement
While police would prefer hunters not to interfere with law enforcement, it is also generally accepted by police that child sexual abuse online is not a problem they alone can solve. De Rond points out that paedophile hunters have been known to catch predators who have not yet shown up on the police radar but are a danger to children. Evidence offered by hunters, usually in the form of screenshots of chats, or graphic images sent by the predator to the decoy, can also help convict them.
In 2019 the BBC asked 45 police forces in England, Wales, Northern Ireland and Jersey to tell them how many convictions relied on evidence supplied by paedophile hunters. Forty-two forces responded. Their data showed that 403 people were prosecuted in 2018 for attempting to meet a child having groomed them online. Of these, 252 involved evidence gathered by hunting groups.
An internal questionnaire completed by police forces in 2023 suggests they used evidence packs produced by hunters in police investigations in 90% of cases.
The legal basis for arresting a suspected predator comes from Section 67 of the Serious Crime Act 2015, making sexual communications with a child a criminal offence. The Court of Appeal has made past determinations that suggest there is no legal difference whether the child in question is real or an adult posing as a child.
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But this does not mean the police are always happy to cooperate, de Rond points out. “Police and hunters don’t tend to talk,” he says. “Police know how effective hunters are, but they can’t endorse them. Unlike with police, where there is the presumption of innocence, predators are not given the benefit of the doubt by hunters. It can be a precarious situation when it comes to dealing with arrests.”
Poor relationships between hunting gangs and the police can mean that prosecutions fail. One problem is the nature of the evidence – reams of chats on social media. The Crown Prosecution Service (CPS), which has to authorise any charges, is often concerned about the copies of online chats being edited, which could compromise the evidence in court.
The CPS will ask for the mobile phone or device used to conduct the chat. This raises problems for the decoys, who may be using the same device to speak to 10 more suspects, which will result in the decoy refusing to give up their phone to the CPS.
Issues also arise when hunters target a person who is already subject to a live police investigation. One police officer quoted in the book says the CPS should make it easier. “I’ve got 26 years in the police now,” the officer says. “If a decoy provides a statement that says, ‘I have handed every communication and everything I have to police,’ that is a statement, that’s a lawful document. Why is it anybody’s place to disbelieve that? It’s gone from trying to prosecute people to finding reasons not to.”
The need to humiliate
There are many hunting groups active in the UK: Wolf Pack Hunters, based in Scotland, are known for their aggressive front-ups (a predator in one sting is treated to a “Glasgow kiss” headbutt); Silent Justice; Keeping Kids Safe; and Cobra. De Rond had to interview for a spot on Cobra. They liked the fact he had spent time with military doctors and nurses in Afghanistan. In 2018 he met Jay and his partner, Saz, in a pub and Jay offered to train him up as a hunter. He went to their semi-detached house “somewhere in middle England … the nerve centre of one of Britain’s most prolific paedophile hunting teams”.
This is where Jay reviews logs between decoys and predators when deciding whether there is sufficient evidence to go out and “light someone up”. Jay has confronted more than 150 predators in his work. Cobra itself has about 45 members today, all unpaid volunteers, working as researchers, decoys and security.
De Rond is particularly interested in the reasons for the sting and the need to humiliate. “If they say all they are interested in is keeping kids safe, then why do the decoys not simply hand over the information to the police?” he asks. “Why carry out the sting and livestream it on Facebook? This is very medieval, in a way.”
According to one 2001 study, about 35% of perpetrators of abuse have experienced abuse themselves, lending some credence to the theory of an abuse cycle: the victim turning into the monster. Yet de Rond found that the reason many of the hunters joined Cobra was that they too were victims of abuse, or had witnessed abuse at a young age. “This creates an interesting conundrum,” he says, “that of survivors of abuse enacting their histories in very different ways – some by abusing other kids and others by hunting down those who do the abusing.”
He admires the tenacity of the hunters. “They’re like a dog with a bone. And they actually do keep children safe.”
Neighbourhoods have a right to know about predators and perverts in their area, hunting groups will argue when asked about their reasons for livestreaming stings. Viewing figures for Cobra’s sting videos can hit a quarter of a million in days on Facebook. Yet despite questions over their methods, de Rond witnessed, first-hand, predators exposed by Cobra being caught and jailed who had discussed abusing real-life children, family members, even sending videos and photographs of children in their care to the decoys – who also sometimes pose as adult women – who in turn hand that evidence to police.
In one case the book describes a harrowing sting where Cobra tracked down a man who was livestreaming his granddaughter to others online while she was in his care. Cobra’s work found him and put a stop to the abuse.
Nationwide, however, there have been a number of cases of mistaken identity by hunting groups. In 2019 the BBC reported how a gay couple, Jordan and Ben, from West Sussex, were falsely accused of trying to meet a child in a sting streamed to thousands of people on Facebook by Yorkshire Child Protectors. They were visiting Jordan’s sister in Hull when they were confronted outside her home. They received homophobic abuse before police arrived to arrest them. Yorkshire Child Protectors apologised, saying they were “heartbroken” for the two innocent men, and said it had received false information.
Last year a barber from Lancashire said his life was ruined after being accused of communicating with children. He was later cleared and a hunting group apologised, saying his Facebook profile had been cloned by the real culprit.
Despite such serious mistakes, police and child protection charities agree that child abuse is a problem on an enormous scale, and that the police do not have the resources or capability to tackle it alone.
The National Society for the Prevention of Cruelty to Children would like police and hunters to cooperate better. “We need to know how police forces and paedophile hunters can work together without jeopardising cases or potentially putting children in danger,” it says.
“In an ideal world the police would be given more resources and hunters would hand over more evidence,” de Rond says. “It is unlikely to happen. But I can’t see that hunting teams are going to disappear any time soon.”
Book extract: Mark de Rond on his first meeting with paedophile hunters
When, in August 2018, I threw my lot in with that of paedophile hunters I quickly found myself in the company of factory foremen, hospital porters and those working on building sites. A few were ex-military and several worked the doors of pubs and nightclubs; and though there was the odd barrister, solicitor, journalist, stockbroker and entrepreneur, white-collar workers seemed the exception.
Government estimates subsequently confirmed my suspicions that those who take up hunting disproportionately represent the working classes. So why do hunters not represent more segments of society, seeing as abusers do? To find out, I reached out to a few teams via Facebook and go on to meet a woman in her late thirties. She looks no different from any of the shopping public except for a big smile. She asks if I’m OK going to ’Spoons for a chat. “Sure,” I say. As we head for the pub, we are joined by three men and a woman.
One of the men wears a red hoodie with the name of his hunting team in white across his arms and back. Another wears blue, a third green. The woman is entirely in black and, unlike the men, wears a facemask featuring razor-sharp teeth. I do a double-take and daren’t look at her again for fear of giving offence. But first impressions deceive and before long, and after an order of drinks, we’ve warmed to each other. Would it be OK if I recorded our conversation, I ask, and, when no one minds, I place my smartphone on the table.
Around a small table, and furthest away from any daylight, the hunters talk with obvious resentment about what brought them to hunting in the first place. They tell me how distrusting they are of the police. The woman in the mask says she was sexually abused by a senior police officer and, using colourful language, says he ended up walking free. The one in a red hoodie was frequently beaten by his dad, who would also lock him up and starve him for days. The one in blue says that as many as eight out of 10 hunters were abused as children. No source is cited but it isn’t hard to believe, for even the police think that hunters represent a disproportionate number of survivors of abuse compared with the general population.
The one in green is sure that predators want to be caught, or some of them anyway, and even if they don’t, “when you show them the evidence you have on them, you can see their arseholes fall out”. “And when you see that happening,” the one in red adds, “it vindicates absolutely everything.”
I am tempted to ask whether people might simply be surprised when suddenly faced with accusations of depravity regardless of whether these are true or not, so to see a target getting scared may not be the most robust indicator of guilt. But I let matters be. There’s no point risking an argument this early in the fieldwork, when everything still feels so delicate. I find it hard not to feel sympathy when listening to their stories of neglect and abuse, and betrayal by those who should have been looking after them.
© Mark de Rond 2025. Extracted from Dark Justice: Inside the World of Paedophile Hunters, to be published on March 6 (Cambridge University Press)
Written by: David Collins
© The Times of London