In 1966, Truman Capote’s In Cold Blood all but created the true crime genre. Nearly 50 years later, radio journalist Sarah Koenig decided the case of a Baltimore high school student, Adnan Syed, convicted of murdering his teenage ex-girlfriend Hae Min Lee, needed a second look. 

With its high production values, conversational style, and a storyline unfolding in real time across episodes, 2014’s Serial fueled a new wave of interest in true crime and transformed podcasting. Its first season — with its piano-plinking earworm of an opening theme and endless parodies — was once the most downloaded podcast in the world at 300 million, a number that now feels almost quaint thanks to the influence Serial has had on the entire medium. 

But Serial’s most consequential effect was on the criminal justice system itself.

Before the landmark series, the main way we received our pop culture narratives about crime came through police procedurals like Law & Order and high-profile investigations like that of O.J. Simpson or JonBenét Ramsey, where the accompanying media circus often overshadowed the facts; serious deconstruction of individual cases was relegated to niche internet forums or the occasional prestige documentary. Even in more routine circumstances, police departments typically controlled the stories around criminal investigations, choosing what the public got to know and when they knew it. This grip on information often meant the media had no choice but to parrot the police narrative of a case — a framing mirrored by the onscreen “copaganda” of procedurals and other scripted shows.

Serial changed that by ushering in an age of increased scrutiny over the narratives we’re fed about policing and by making millions of listeners more fundamentally aware of the limits and flaws of the justice system. From that awareness has come serious action that arguably helped free Serial’s own subject.

Much has been made of the ways in which the true crime podcasting boom may have normalized the more negative stereotypes of the genre: obsessed fans harassing suspects and thinking they know better than authorities, or boozed-up white women joking about murder as millions of fans laugh along without regard for victims or survivors. To be sure, thorny complications can arise, but little attention has been given to the positive outcomes of this kind of collectivism when it’s applied to an unjust system.

True crime podcasts, starting with Serial and the high-profile podcasts that followed, “have offered a critical lens through which to scrutinize the procedures and decision-making in the criminal justice system,” Kent Bausman, a criminologist and sociology professor at Maryville University, told Vox in an email. “They have enlightened the public consciousness about the convoluted machinations of the system and revealed with great clarity the human experience of miscarriages of justice.” Bausman noted that true crime podcasts frequently provide insight into “everything from the production and use of false confessions and the inherent problems that exist regarding the use of forensic evidence in the courtroom.”

Bausman pointed out that organizations like the Innocence Project have existed for decades, yet it’s only recently that they’ve become better known as a result of the true crime explosion. We’ve gained a broader cultural awareness of the factors that lead to the wrongful convictions that the Innocence Project and its peers help overturn — things like false confessions, police misconduct, bad forensics, and false testimony at trial. Additionally, terms like “Missing White Woman Syndrome” and “Missing and Murdered Indigenous Women” have sprung up to encompass an entire range of police inadequacies when it comes to the racial and socioeconomic gaps between “perfect” victims and forgotten ones.

True crime fans are now loud advocates for thorough investigations. They’re more knowledgeable about shady criminal justice techniques, from entrapment and “Mr. Big” operations to Brady violations and the Reid technique. There’s an increased familiarity with nonprofits that help law enforcement solve cases, from Texas EquuSearch to the DNA Doe project, as well as those that seek criminal justice reform, like End the Backlog.

Several of these organizations build upon what is perhaps the biggest recent breakthrough in criminal investigations: forensic genealogy. The use of familial DNA to catch culprits has revolutionized crime-solving amid the true crime boom. In 2018, when forensic genealogy led to the capture of the Golden State Killer, the true crime world greeted the announcement like sports fans might celebrate winning the World Series — a comparison that captures the complicated nature of a genre that makes entertainment out of tragedy. Wider concerns about genealogical privacy and private companies sharing user information quickly followed.

That collectivity and the sense that a “true crime community” exists also largely came about because of Serial.  After Serial, millions of people became amateur detectives. Legions of fans have made themselves an invaluable part of the crime-solving process via social media, as well as longtime true crime forums like Websleuths. They’ve pored over cases until they’ve become nigh experts themselves, drummed up tips to law enforcement, generated new interest in cold cases, and often all but led authorities by the nose to conclusions they should have reached long ago; in one famous case, this latter scenario played out before the ears of millions of listeners after an amateur sleuth made his own podcast to draw attention to the Kristin Smart case and forced his local cops to pay attention. 

Journalist-led true crime podcasts have also had a direct impact on the cases they’ve investigated in the intervening years — like In the Dark, which helped free its season two subject, Curtis Flowers, from death row in 2019. In 2022, the runaway hit Murdaugh Murders helped catalyze the re-investigation of the death of Stephen Smith, which is widely believed to be connected to the byzantine crimes of Alex Murdaugh. 

Not all criminal investigations benefit from millions of newly minted amateur sleuths diving into the fray. Bausman warns it can in fact “commodify both offenders and victims for the public’s amusement.” He also pointed out that despite the renewed attention true crime podcasts can bring to stagnant investigations, the clearance rates for homicide cold cases have not increased due to this influence. 

Still, Serial continues to have an outsized impact on our cultural understanding of the criminal justice system, and this sea change ultimately came full circle back to Adnan Syed. 

In 2022, Syed’s hometown of Baltimore revisited dozens of convictions as part of a larger overall effort by Maryland to atone for decades of draconian sentences handed out to juvenile and young offenders, many of whom spent their entire adult lives in prison with no opportunity for parole. This is just one example of how prosecutorial divisions across the country are reexamining wrongful and unfair convictions through what are known as conviction integrity units and sentencing review units. These programs are part of the normalization of criminal justice reform that has come amid an enormous shift in attitudes about prosecutions in the decade since Serial aired.

It was a dogged pursuit of local criminal justice reform that allowed Syed to finally walk free, though the flashier “whodunit” aspects of his case that initially attracted Koenig also delivered a twist. Syed’s case review uncovered new evidence, including two new suspects, that cast reasonable doubt on his trial and conviction. Prosecutors dropped all charges against Syed just days later; they later walked this back on a technicality. Those nuances also reflect a post-Serial shift in public advocacy and focus: on the rights of victims and their families in cases like this one.

Although his case is still in limbo, Syed remains out of jail, his conviction stayed until Hae Min Lee’s family’s concerns can be resolved. It’s the kind of messy, satisfyingly unsatisfying conclusion that befits both Serial itself and the evolved criminal justice era we’re in — one in which answers rarely come easily, but for perhaps the first time, all of us are looking.