Although the story you are about to read involves a fugitive, law enforcement and a six-month chase across Mexico, for Billy Jensen it was just another day on the job. In 2017, Jensen was on the hunt for a pale, ginger, tattooed California killer hiding out in Mexico. Jensen uploaded a photo of the fugitive to Facebook. “¿Has visto a este hombre?” he asked, using Facebook’s targeted ad tools to ensure the post was seen by people living near American bars. Tips came flooding in. One tipster snapped a photo. In just 24 hours, Jensen had his guy. Unfortunately, the killer was on the move. It took half a year of similar posts for the 49-year-old Jensen to finally get the suspect apprehended by the Mexican police – for Jensen isn’t a police officer himself, or a detective, or an FBI agent. He is a podcaster, author, journalist, and self-described “citizen sleuth”. True crime has a long history (in the 18th century, the British public devoured the Newgate Calendar, a record of contemporary crimes and executions), but we have never had so much access to bingeable barbarity. Netflix hosts so many true-crime docs that the Washington Post once asked, “Does Netflix have a killer problem?” This autumn, Channel 4 is planning to launch an entire platform dedicated to the genre, two years after Sky launched its true-crime channel. The market is so saturated that Hulu recently debuted a parody show, Only Murders in the Building. The boom continues to influence real-life investigations. The trial of real estate heir Robert Durst, who was found guilty of the murder of friend and journalist Susan Berman in 2000 two weeks ago, was made possible after he was caught on tape seemingly confessing in the HBO miniseries The Jinx; the jury was shown clips on the first day of the trial. In April, California authorities arrested a suspect in a 25-year-old missing persons case, thanking the eight-part podcast Your Own Backyard for enabling them to interview new witnesses. In 2020, a convicted serial killer confessed to another murder on the podcast Where the Bodies Are Buried. In 2018, a husband was charged with his wife’s murder after the Australian podcast The Teacher’s Pet brought renewed attention to the case. Even the authorities have cottoned on: two years ago, Dutch police launched De Politie podcast to encourage witnesses to come forward about a 1991 cold case. Several tipoffs contained useful information. Whether we like it or not, true-crime docs and podcasts are playing a role in the criminal justice system – but is that role always as helpful as podcasters and documentarians like to make it seem? How exactly are citizen sleuths transforming the implementation and perception of justice? Our true-crime frenzy started with Serial – the 2014 murder investigation podcast that was downloaded more than 80m times – but where will it end? “I wouldn’t make a good detective because I don’t follow rules incredibly well,” Jensen says. He has a master’s degree in religious studies and began working as a crime reporter in 1999. After decades of writing “stories with no endings”, he decided to try solving crimes in 2016. Capturing a homicidal fugitive such as his tattooed Californian wasn’t especially unusual for Jensen: his website claims he has helped solve 10 homicides and had a hand in locating numerous missing people. In 2020, one of his podcasts, The Murder Squad, led to the arrest of a suspect in a 40-year-old cold case after Jensen and his co-host, the former cold-case investigator Paul Holes, encouraged listeners to upload their DNA to genealogy database GEDmatch. Law enforcement are increasingly using services such as these to track down criminals such as Joseph James DeAngelo Jr, more widely known as the Golden State Killer – a name coined by another citizen sleuth, Michelle McNamara, author of the book behind HBO’s series I’ll Be Gone in the Dark. “We can do a lot more,” Jensen says when asked why he went into true crime instead of becoming a detective. (He pursued a job with the FBI after graduating, but had to drop his application after his father became sick.) “While [police] have a lot more power in the sense that they can get a search warrant, as a writer and as a podcaster, I can do a lot more … If a suspect tells the police: ‘I don’t want to talk to you, I want my lawyer,’ they can’t talk to them any more. I could keep going until someone says: ‘You’re harassing me.’” Jensen does abide by some rules. His journalism experience means he knows how to pursue tips, check facts and stay legally and ethically accountable, but not all true-crime podcasters are as scrupulous. Across social media, amateur sleuths are currently prying into the death of 22-year-old Gabby Petito, who went missing in September while travelling across the US with her fiance. More than 600m people have viewed #GabbyPetito TikToks; on Instagram, an account with nearly 60,000 followers posts infographics emblazoned with short, sharp sentences such as “Cops know more than they’re saying”. An ABC reporter who spoke with law enforcement said they had “run into trouble corroborating facts and disproving false narratives about the case before they are published widely online”. And after the disappearance of Sarah Everard in March, sleuths began speculating how fast she’d be able to run from an attacker based on her records in the running app Strava; and admins on one online forum had to close down a thread about Everard after posters began digging into the social media pages of her family and friends. In February 2017, the bodies of 13-year-old Abigail Williams and 14-year-old Liberty German were found not far from the trail where they had been hiking in Indiana. Before she died, German had the foresight to record an encounter with a man who was following them. These audio and video snippets are immensely popular with internet sleuths, some of whom have named and shared pictures of the girls’ Facebook friends who they falsely accuse of being the killer. The danger of this kind of behaviour was demonstrated in 2013, when Redditors falsely accused a student of orchestrating the Boston Bombing, flooding his family with hateful messages and phone calls. It is not just the families of the falsely accused who have been troubled by true-crime fanaticism. The family of Hae Min Lee, whose murder was at the centre of Serial’s first series, spoke of “reopened wounds” when the convicted murderer sought a retrial after the podcast became a hit. Earlier this year, the family of a Chinese man murdered in 2003 threatened to sue producers of an upcoming film based on the story of his death. “Many of these families feel like no one has ever listened, and it is very empowering for them to feel heard,” Marissa Jones says. She hosts a US podcast called The Vanished, which centres the friends and families of missing people in its storytelling. It has been downloaded 51m times; 90% of its audience are women. Jones’s podcast focuses on victims who are traditionally ignored by the media. “True crime as a genre is too often focused on the offender,” Jones says – and there is a disturbing amount of killer-themed merchandise available online, from wrapping paper to tea towels. Lili Pâquet, a writing lecturer at the University of New England (Australia), has studied how victims abandoned by formal justice systems can get “informal justice” through true-crime content. “One of the things I noticed with both Trace and The Teacher’s Pet was that the narrators had access to impressive community grapevines, something the police in both investigations clearly lacked,” Pâquet says. “The grapevines brought up new evidence and witnesses.” Jones says that tips from her audience mean that multiple investigations have been reopened. In 2018, she interviewed the husband of a missing woman who had refused to speak with the police for decades, their conversation opening the door for detectives to try him again, which ultimately led to his murder conviction. Jensen and Jones both work directly with law enforcement; they are not vigilantes. If a police department tells him to drop an investigation because it is close to apprehending a suspect, Jensen listens. But true crime reporting does not just affect the distribution of justice; it has a huge effect on the public’s perception of it. The genre as a whole is obsessed with stories of rape and murder that can warp the perspectives of the audience – mostly women – who consume this content. Dawn Cecil, a criminology professor at the University of South Florida and the author of Fear, Justice & Modern True Crime, argues that true crime creates perceptions of a fallible justice system or outright distrust in authorities, depending on who you’re listening to. “It is great when a podcaster unearths new evidence that is reputable and can help. But I think those instances are rare,” Cecil says. She is concerned that podcasters and their listeners, who have no investigative experience, waste police time and resources by turning over evidence that is ultimately useless. “There have been instances in the US in which the police have asked people to stop interfering as they had identified an innocent person as the suspect,” she says – such as in 2019, when an Indiana sheriff’s office investigating the case of the two hiking girls rebuked the online sleuths (“Please STOP,” its Facebook status read. “You are ruining innocent people’s lives”). There are a number of other ways in which unqualified sleuths can do more harm than good: using insensitive language when talking about victims, distressing families, or potentially prejudicing court cases. For his part, Jensen says if he “gets loud” about certain cases, it can put pressure on police departments. “I think the more true-crime storytelling, the better,” Jensen says. “I think that there are so many unsolved murders and missing persons out there for a thousand podcasts. Let’s dig in deep, find those stories, and tell them, because right now, those stories are sitting in dusty evidence lockers … If we find those cases, then it is a force for good.”