We're all amateur armchair detectives now. From Anne Enright who pondered the Madeleine McCann disappearance by measuring distances on Google Earth and ruled out the possibility of wife swapping (because "one of the wives had brought her mother along"), to Coleen Rooney whose 'Wagatha Christie' moment gripped the Twitterverse last year - nobody is immune to the grim joy of freelance sleuthing.
Week after week, TV detectives move laconically through their scenes, and we sink deeper into our couches, drinking it in like warm cocoa and indulging ourselves in whodunnit parlour games. True crime has migrated from pulp fiction and trashy women's magazines, to become a respectable and mainstream genre, while a neverending stream of procedural shows have helped us gain a kind of vicarious expertise on admissibility and evidentiary rules.
Thanks to Line of Duty, we know about being questioned by an officer of one rank senior. We hazily understand about blood coagulation times, DNA evidence and criminal body language, and we are pretty sure we have most crimes long figured out before a verdict is announced. Indeed, some of us are now such crime savants that we don't even need an investigation. Whether in fiction or in real life, my mother, for instance, "just knows" when someone is guilty, because they have "that face". The rest of us must skill-up using TV, however.
First, it's important to remember that there is a huge distinction between crime procedurals and crime documentaries. Some series leaven their plots with a little more or a little less realism - Law and Order is much more true to life than CSI ever was - but, for the most part, the detective procedural is the very definition of fiction. Detectives are often shown threatening suspects, something that would collapse an investigation in real life, and undercover cops have to identify themselves when asked, which, in reality, they don't.
One thing they do teach us is that waiving your right to a lawyer because you think the cops haven't a chance of nailing you, as the characters on The Closer often do, is a bad idea - especially if Brenda Leigh Johnson (Kyra Sedgwick) turns out to be your interrogator. They also show that not all shredders are created equal. In NCIS and Better Call Saul, legal documents can be pieced together from a strip-cut shredder. A cross-cut shredder is much more secure - even Abby on NCIS admitted she was "good but not that good" and could not reconstruct the documents after they went through one of those.
Latterly, however, the greatest shows of the genre don't really rely on the nitty-gritty of procedure. The Wire, for instance, was almost anti-procedural; as creator David Simon put in his pitch for the show, this was "not so much about the dogged police pursuit of the bad guys but rather a Greek tragedy".
And so for our real detective matriculation, we turn to true crime documentaries, where the True Crime Lesson Number One - yes, it's obnoxious, but, sadly, also true - is that being hot changes everything. In terms of being critical to the investigation, it's up there with wearing gloves and sealing off the crime scene.
If you're hot and you didn't do it - like Amanda Knox - that doesn't mean there won't be a variety of documentaries examining whether you might have done it. Journalistic interest will fuel prosecutor's zeal and before you know it, there will have been various appeals, you're a cause celebre.
If you're hot and you did do it - like Ted Bundy - this also changes everything. It means that after a while people will forget the names of your victims and just focus on how dreamy you were. They'll enlist a movie star to play you (in Bundy's case, Zac Efron). No article will ever be written about you without mentioning the word 'charming.'
Even for victims, there is a 'law of attraction'. It means more resources will be devoted to finding out whodunnit. When child beauty queen JonBenet Ramsey was murdered, her minor celebrity as an underage pageant winner was pivotal in ensuring the police investigation dragged on for years. When Sophie Toscan Du Plantier was murdered in west Cork, her pre-Raphaelite gorgeousness helped ensure that an army of amateur detectives would be marshalled into action: West Cork, a 13-part podcast series on Du Plantier's disappearance, was a global hit when it aired two years ago.
True Crime Lesson Number Two is 'don't push your luck if they haven't caught you yet'. The concomitant takeaway for amateur investigators is: beware the grieving camera hog. Last year, when Channel 5 aired yet another documentary on the Soham murders, the striking thing was how the killer, Ian Huntley, had installed himself centre stage as far as local media were concerned. When TV3's Ireland's Most Shocking Crimes covered the murder of Rachel O'Reilly by her husband, Joe, the most jaw-dropping thing - besides the killing itself - was how O'Reilly brazenly went on the Late Late to talk about Rachel's disappearance. In hindsight, it all seemed so obvious. Joe, more than any criminal in recent memory, certainly had "that face".
In Sky's Faking It: Tears of a Crime we do an even deeper dive into the tell-tale appearance and body language signs that we have a killer on our hands. Ears turning red is a big thing, apparently - it shows that blood pressure and stress are rising, which can also be signs that porkies are being told. The show also teaches us that bad actors don't tend to do their research. When Karen Matthews, who secretly helped to orchestrate the kidnapping of her daughter, Shannon - subject of both a TV drama and a documentary focussing on Matthews' body language - appeared at a press conference to appeal for help, there were, according to experts, tell-tale gestural slips that all was not as she claimed. And although Matthews clutched a teddy, the bear wasn't her daughter's.
There is apparently a thing called 'deception euphoria' where an interrogated criminal lets out a little smile of satisfaction in the midst of a great performance. According to the documentary series Faking It: Tears Of A Crime, this is what former EastEnders actress Jennie Grey apparently did during her filmed conversation with police after her partner, Ben Butler, murdered their daughter Ellie in 2016.
Sadly, many crime series and podcasts bear out the notion that men who commit sex crimes often get away with it. Netflix's Unbelievable is based on the true story of a young woman who reported a rape but was not believed by police, while in Dig, an NPR true crime podcast, a woman told Louisville police she was raped, and initially wasn't believed, despite the fact that a man's DNA was found on her body. Then, a prosecutor in Kentucky rejected the case. The episode, which caused widespread outrage, shows how the criminal justice system remains skewed against victims.
The news and prime-time crime dramas often condition us to the idea that murders are usually sewn up. What the surge of podcasts and true crime documentaries have shown is that real-life investigations are often messy and unresolved. By the end of The Devil Next Door, on Netflix, we are not clear, even after being shown two trials and two deportations, if Ukrainian-American auto worker John Demjanjuk really was the notorious Holocaust-era killer, Ivan The Terrible.
In Serial, which recently set a podcast world record (some episodes have been downloaded 340 million times), the story of Hae Min Lee's 1999 murder - and her ex-boyfriend Adnan Syed, who was convicted of the crime but has maintained his innocence - left listeners without clear answers. Lee's murder became a detective story, a whack-a-mole of clues and red herrings in a story populated by characters with secrets to hide. "It became about anyone but Lee," Vanity Fair noted, "as finding her murderer turned into a game that amateur sleuths were trying to win."
And perhaps amateur detective work is not without its consequences. It gives us an illusion of expertise, which can cause huge problems in real life case-building. The so-called 'CSI effect' in the American legal system refers to the increasing demand by jurors for more and more forensic evidence, something that has the net effect of actually raising the burden of proof for prosecutors.
What's even more interesting is that it has been suggested that the glut of crime shows have served as a sort of unofficial guide for would-be criminals on how to get away with it. In a post-Sopranos world, surely only the sloppiest hit man doesn't don a pair of gloves or invest in some good bleach, for instance? In 2012, the FBI caught a serial killer - Israel Keyes - who had "read Mindhunter and watched CSI", according to the author of a book on him, and "knew what not to leave behind".
Happily, a lot of the research has put this notion to bed. A 2018 study by the University of Mainz in Germany looked at statistics from the databases of the FBI and its German equivalent, the Bundeskriminalamt (BKA), and compared the crime-detection rates during the years preceding the launch of the CSI series with the subsequent rates. Then they asked 24 convicted criminals in prisons for their opinions on series such as CSI and whether they thought such shows could help when it came to escaping prosecution. The researchers put together a complex experimental design to find out whether viewers of TV shows like CSI would actually be better equipped to conceal the traces of a crime. Overall, the researchers did not find any connection between watching forensic dramas and the ability to successfully avoid detection after committing a crime.
Just as Breaking Bad didn't show anyone how to make drugs, crime shows are not really a how-to. And that surely gives the rest of us the all-clear to keep watching - and keep sleuthing.