The Sixth Commandment true story explored in unsettling Catching a Killer documentary that sheds light on quest to bring Ben Field to justice

The Sixth Commandment true story is explored through the perspective of investigators and family members in the Catching a Killer series

The Sixth Commandment true story explored in Channel 4 documentary. Seen here are (Éanna Hardwicke as Ben Field and Timothy Spall as Peter Farquhar in the BBC drama
(Image credit: BBC/Wild Mercury)

The Sixth Commandment true story is every bit as heart-wrenching as the BBC drama suggests and it’s also the focus of a particularly chilling episode of a true crime documentary.

The Sixth Commandment true story is currently being brought to life in the BBC’s chilling new drama, starring Timothy Spall, Anne Reid and Éanna Hardwicke, and these devastating events are still deeply felt. Ben Field’s crimes were committed less than a decade ago as he manipulated his way into the lives of Peter Farquhar and Ann Moore-Martin, and persuaded them to change their wills, before murdering Peter. The Sixth Commandment depicts his reign of terror and whilst some people might be wondering what happened to Ben Field, others might be interested in learning more about how he was apprehended for his appalling crimes. 

Here we reveal how The Sixth Commandment true story is explored in the Catching a Killer documentary and how you can watch it as the BBC drama continues… 

*Warning: Spoilers for The Sixth Commandment true story ahead*

Peter Farquhar (TIMOTHY SPALL)

(Image credit: BBC/Wild Mercury/Amanda Searle)

What is Catching a Killer and does it tell The Sixth Commandment true story? 

After watching a particularly emotive true crime series like Manhunt or Steeltown Murders it’s perhaps no surprise that some people might want to discover more about the real cases that inspired them. Anyone wanting to know about The Sixth Commandment true story might find Channel 4’s Catching a Killer what they’ve been looking for. This is a documentary series that premiered in 2017 and the most recent episode, A Diary From the Grave, which was released in 2020 explores what happened to Peter Farquhar and Ann Moore-Martin. 

The episode focuses on the investigation of the Thames Valley Police detectives and the exhumation of Peter’s body two years after he passed away in 2015. As revealed by his friend and former mentee, Michael Crick, in a heartfelt piece for The Times, Field had apparently alleged to Peter’s friends and family during their relationship that the retired teacher had a problem with alcohol. 

When Peter was found dead on his sofa with a bottle of whiskey beside him, the scene had been staged to convince investigators that his passing was alcohol-related. In Catching a Killer’s A Diary From the Grave, it’s revealed how Peter’s death was looked into again after suspicions about Field were raised following Ann Moore-Martin’s death from natural causes in 2017.  

Ann Moore Martin (ANNE REID)

(Image credit: BBC/Wild Mercury/Amanda Searle)

The episode opens with audio clips from emergency services calls made for Peter and Ann, as well as an audio recording remarking upon the biblical Sixth Commandment - Thou Shalt Not Kill. Footage is included of the senior investigating officer and his fellow detectives looking into Peter and Ann’s deaths as they worked on the case and fixed Field firmly in their sights as the prime suspect. 

The documentary charts the investigation from a point where Field was initially unaware he was being investigated at all. A Diary From the Grave follows the officers involved, who give first-hand accounts to camera of their thoughts and processes, and also features Peter Farquhar’s brother Ian as he is told of the investigation into Peter’s death and opens up about losing him and his memories of the retired teacher and lecturer, giving viewers more of an insight into Peter’s life and personality.  

Peter Farquhar (TIMOTHY SPALL)

(Image credit: BBC/Wild Mercury/Amanda Searle)

The Catching a Killer episode got its name from the journals that Peter kept and glimpses of actual diary entries are briefly shown during the course of the episode being read by Ian, with a voiceover narration of some passages too. The journals were also looked into by the police in depth as they conducted their investigation, as revealed in the documentary. 

So ultimately, The Catching a Killer documentary episode does tell The Sixth Commandment true story but through the more specific lens of the police’s attempts to secure evidence and arrest Ben Field for his crimes. It also showcases the deeply personal nature of this case to so many, showcasing the huge impact Peter made on so many people's lives as a teacher, brother and friend.

How to watch Catching a Killer’s A Diary From the Grave  

If you've already watched to the end of the drama on BBC iPlayer and want to know more about The Sixth Commandment true story or would simply prefer to learn more about this shocking case in factual form, then UK viewers can watch Catching a Killer for free via Channel 4. Here you can immerse yourself in the police's quest for justice in A Diary from the Grave, as well three other episodes in this true crime documentary series which each focus on different cases.


(Image credit: BBC/Wild Mercury/Amanda Searle)

Sadly, if you’re going to be on vacation abroad when you want to watch Catching a Killer, A Diary From the Grave, then you won’t be able to watch as you normally would at home. Luckily there’s an easy solution and you can use a VPN to continue watching. This is a handy bit of software that changes your IP address so that you can access on-demand content or live TV just as if you were at home.

Our sister site, TechRadar, has tested all of the major VPN services and they rate ExpressVPN as the absolute best. They say, “It’s compatible with all of your devices, supports most streaming services, and ranks among the fastest. You can even install it on devices like an Amazon Fire TV Stick, Apple TV, Xbox, and PlayStation. So for a one-stop-shop, you can’t go wrong with Express.”  


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Ranked among one of the fastest VPN providers, this risk-free service is also compatible with all of your devices. Enjoy access to almost any streaming service, and if you don't like it there's a 30-day money-back guarantee.

If you've never installed a VPN before, don't worry, it's quick and easy. Just follow these three steps:

  1. Download and install the VPN following ExpressVPN's easy-to-follow instructions.
  2. Once you've installed your VPN, open the app and select your server location as anywhere in the UK.
  3. With your VPN installed and server location set to UK, you can now watch Catching a Killer online. 

VPN disclaimer

(Image credit: Future)
Emma Shacklock

Emma is a Royal Editor with eight years experience working in publishing. Her specialist areas include the British Royal Family, ranging from protocol to outfits. Alongside putting her royal knowledge to good use, Emma knows all there is to know about the latest TV shows on the BBC, ITV and more. When she’s not writing about the next unmissable show to add to your to-watch list or delving into royal protocol, Emma enjoys cooking, long walks and watching yet more crime dramas!