The prisoners seemed to me in no way morally inferior to the rest of the population though they were on the whole slightly below the usual level of intelligence, as is shown by their having been caught.

BERTRAND RUSSELL, AUTOBIOGRAPHY, 1967

The basis on which the investigation of crime stands is the assembling of a sequence of facts allowing the judicial process to be carried through to a satisfactory conclusion. It should prove that a crime was committed, and should also present evidence that a named person, or persons, was responsible for committing it. During Operation Darcy, police used every trick in the book to catch and bring to justice Dennehy, Stretch, Layton and Moore. Indeed, they employed state-of-the-art surveillance systems to great effect and forensics played a great part. So, if committing a serious crime, or any crime, is in your mind, forget it. The odds are you’ll get caught.

The earliest-known treatise on forensic medicine (the word ‘forensic’ meaning no more than ‘connected to the courtroom’) is the thirteenth-century Chinese book Hsi Yuan Lu (The Washing Away of Wrongs). Above all else, this work stressed the importance of examining a crime scene, stating: ‘The difference of a hair is of the difference of a thousand li’ – a li being a Chinese mile. This adage reflects the importance placed on trace evidence in whichever form it takes by the French criminologist Dr Edmond Locard at the University of Lyon who, early in the twentieth century, recognised the value of trace evidence and advanced his ‘contact trace theory’, which states simply: ‘That a criminal will always carry away with him some trace from the scene of his crime, and leave some of his presence behind’.

This is the very foundation of forensic science. It is these objective traces, which the criminal unwittingly deposits as clues, along with subjective traces such as witness statements that conspire to prove the ‘named person or persons’ responsible for a crime. This tangible evidence will, these days, be subject to analysis and comparison in one or other of the specialised sections of the modern forensic science laboratory and the range of possible interchanges is vast.

Harry Sodeman, a distinguished Swedish scientist criminologist, wrote that ‘everything imaginable may constitute a clue’. Everything that is, from earwax to ski tracks. Earwax traps dust particles from the environment and may yield information about a person’s occupation, while looking at ski tracks tells the experienced observer the direction the traveller was moving – usually downhill. The list of contact traces includes blood, glass particles, dust, fibres, hair, body-fluid stains, oil, paint, fragments of vegetation and a great many more substances, restricted only by the limits of scientific detection methods – which today are very few and far between.

For instance, if archeologists can determine from the preserved body of a man buried in an icy glazier 100,000 years ago what he ate for his last supper, his diet, age and occupation, then today forensic pathologists and scientists will know more about you than you did before you died. And, believe it or not, one can get chemical fingerprints from smoke, which is especially useful when determining the crime of arson and use of an accelerant. But we’ll leave these fascinating forensic issues for another day. However, what Dr Edmond Locard could never have conceived is nowadays one can pluck contact trace evidence from thin air – indeed, out of clear blue sky, even space – and it is as damning to the offender as any type of physical evidence or DNA matching. Enter stage left, your mobile provider!

From the very moment one purchases a mobile telephone, be it on contract or Pay-as-you-Go, ‘Big Brother’ starts watching you – yes YOU! The telephone providers know your full name, your address, your credit rating, if you are employed or otherwise. And you can bet your bottom dollar that buried in the small print, the very small print of the 15,000-word contract is a clause stating that your provider can share your personal data with anyone they choose – such as those firms who ring at all hours of the day informing you that you can claim thousands of pounds for the road traffic accident you never had, but it gets even better. If the CIA took an interest in a taxi trip you booked using your mobile – or ‘cellphone’, as our cousins across ‘The Pond’ insist on calling them – they can find out in minutes and plot your movements to within a yard or so.

Then there are the ‘APPS’. If your suspicious partner buys one of these surveillance apps, he/she can monitor your movements via Global Positioning Satellites (GPS), 24/7. Switching your phone off while between the sheets with your lover is of no use at all. Your route to a hotel, or apartment, can be traced in a heartbeat because your phone still emits a signal. So, wherever you go, anywhere in the world Big Brother may be covertly watching you. Take this as Gospel, even more so because every phone provider has its own police liaison officer who works hand in hand with detectives investigating a crime where a mobile phone plays some part.

According to the Mail on Sunday, 12 October 2014, at the headquarters of every police force in Britain is a small office called the ‘Telecoms Intelligence Unit’ (TIU). There, police can log in directly to the mainframe computers of three of four big mobile phone companies – Vodafone, Three and EE – as well as BT and internet service providers. EE comprises the former networks Orange and T-Mobile, whose law-enforcement interface was called ‘Plod’ – an acronym for Police Liaison On-screen Database.

Armed with the required usernames and passwords (the method by which police do this I cannot reveal to the reader), in a few keystrokes officers can retrieve confidential data from anyone’s telephone or computer use within minutes. All it takes is a couple of senior officers within the force to sign off the request and any officer can have those details on his screen.

Telecoms security expert Martin Hoskins, Privacy Counsulting, has said: ‘It’s going on every hour of every day. As long as the police have the authorization for the data, the door is always open for them,’ adding, ‘Quick access to communication data can be a matter of life or death if, for example, you’re trying to trace a child carrying a mobile phone.’

The use of electronic mobile telephone data proved crucial as forensic contact trace evidence during the early stages of Operation Darcy. It allowed DCI Martin Brunning and Team (3) of the Major Crime Unit to piece together the movements of Joanne Dennehy, Gary Stretch and Leslie Layton around the times the three murders were committed and thereafter to Robert Moore, who harboured Dennehy and Stretch for two nights while they were on the run.

This mobile phone data put Dennehy (who now had Chapman’s phone in her possession), Stretch and Layton’s ‘Pay-as-You-Go’ mobile phones near a telecommunications mast close to Yaxley at the time when Kevin Lee’s Ford Mondeo was set ablaze.

Ironically, the Yaxley telephonic data only came to the notice of the police because Cristina Lee, already suspicious about her husband’s activities, was concerned as to his whereabouts during the evening he went missing. She had already established that he was having an affair because Kevin had allegedly confirmed it so she checked his mobile phone statements. A well-used number was Dennehy’s, although she probably did not know the name at the time. Cristina rang the number and it was that call which police would say proved that Dennehy was in the vicinity of Kevin’s car when it went up in smoke.

Joanne Dennehy’s name was now in the frame. Then a second piece of electronic forensic contact evidence came about following the murder of John Chapman. She had used the dead man’s mobile phone to sing a song to Gary Stretch – a mistake that all but invited her arrest. Now Stretch’s name was in the frame, too.

Some time after Leslie Layton was arrested, police found the ‘erased’ photo of Chapman’s dead body as a callous souvenir on his mobile phone. This matrix of electronic mobile phone interchanges between Dennehy, Stretch, Layton and Moore was as strong as steel wire. It provided a web from which even the spiders that spun it could not escape.

This was circumstantial evidence in its purest form because it gave the police solid links to the deaths of Kevin Lee, John Chapman, Lukasz Slaboszewski, the addresses of 38 Bifield, and 11 Rolleston Garth; later to prove that Dennehy, Stretch and Layton’s mobile phones were in the near vicinity of the fire that destroyed Kevin Lee’s car, and the ditches where the bodies were dumped at the relevant times in question – all proving forensic contact trace evidence can be plucked out of thin air, even space.

Edmond Locard would now be delighted – can we agree on this? But back then he would not have known about the coming advent of CCTV or the Automatic Number Plate Recognition (ANPR) system either, for the combination of telephonic data, CCTV and ANPR was to rubber stamp Denney, Stretch, Layton and Moore’s downfall.

Despite some bickering as to the exact number of cameras, current research shows that there are about 1.85 million CCTVs in use – one for every 32 people in the UK. It is thought that on average a person passes by one of these cameras at least eight times a day. While on the run Dennehy and Stretch would pass scores of them.

Unknown to police, Dennehy and Stretch, a gun tucked into the waistband of his trousers, were at the time in the green Vauxhall Astra paid for by Kevin Lee. On the night 29/30 March 2013 they stayed with Robert Moore at his council flat at 78 Belvoir Way, Peterborough

Now alone at an empty 38 Bifield, the weak-willed Leslie Layton was falling apart at the seams. As Judge Robin Godfrey Spencer later concluded: ‘Over that Easter weekend Layton was undoubtedly wracked with guilt and worry at what he had done. This is why his friends, Toni Ann Roberts and Michelle Bowles, described him as distressed and upset on the Sunday evening when they spoke to him.’

Besides, where was John Chapman?

However, this guilt and worry did not extend to Layton assisting the police in getting to the truth. When first interviewed he went out of his way to try and cover not only his tracks, but those of Dennehy and Stretch too. When asked about the whereabouts of John Chapman, his take was, ‘I know nuffink, honest to God. I fink I last saw him on Wednesday or Thursday.’ Then, when the cops went away, the first thing he did was to text Moore, and then Dennehy, telling her the police were trying to find her.

The police visited Layton again during the afternoon of April Fool’s Day – Monday, 1 April. Once again he claimed ignorance of the entire business. During this interview Dennehy phoned Layton on Chapman’s mobile phone and as soon as the police left him, he called her back to update her on the progress of the investigation.

By now the murder of Kevin Lee was headline news. On the Sunday, Dennehy and Stretch drove to East Anglia. On arrival at King’s Lynn they stopped off at a friend of Joanne’s called Georgina Page. They talked in a matter-of-fact way about the murders, with garrulous Stretch boasting to Georgina that the bodies would never be found. Georgina would later testify that Joanne became excited and animated when she saw reports on television that she was wanted in connection with the murder of Kevin Lee (the bodies of John Chapman and Lukasz Slaboszewski were yet to be found). ‘She was ecstatic,’ testified Page at the trial. Dennehy then went on to explain to her that she had dressed Kevin Lee up, had ‘lubricated his backside’ and ‘shoved something into it to make it look as though it was a sexual act’.

Before the fugitives left Georgina flat, Stretch threatened her, saying he would get his father to sort out anyone who grassed, which she took to mean that she would be killed. For her part Dennehy said that she had already accepted they would be caught and would go to prison for a long time. With this, Stretch laughed and said: ‘My kids are grown up now, so I don’t care.’ After leaving King’s Lynn he burgled a holiday home at Diss. Amongst the property stolen was an expensive camera. Dennehy and Stretch then received another text message from Robert Moore, telling them they could stay a second night at his place. He had food waiting and wished them good luck.

Early in the morning of Tuesday, 2 April, with a duvet spread across the back seat of their car, Dennehy and Stretch left Peterborough to drive west towards Herefordshire. It was a place that Stretch knew well because he had been born there and periodically lived on and off there – while not in prison, that is.

The couple were filmed by CCTV walking hand in hand at a service station in Market Harborough, south of Leicester, then later at Strensham Services where another camera tracked them to the green Vauxhall Astra bearing the registration number R660 ECT. The police immediately flagged this car as a ‘vehicle of interest’ and added it to the Automatic Number Plate Recognition (ANPR) system. A check through the Motor Insurers Bureau (MIB) revealed the vehicle as being insured by one Gary Stretch of Messrs Undertaker & Co. Now the pieces of the crime puzzle were fitting into place: Stretch was a known associate of Dennehy and she was wanted for murder.

From Strensham in Worcestershire they drove, via Ledbury, to Bartestree, Hereford, where they were once again seen recorded on a store CCTV before Stretch arrived back at his old haunt of Kington, on the Welsh border, and about twenty miles from Hereford. There he met up with a criminal associate called Andrew Wilmott, aka ‘Moby’, at his flat in Llwellin Road. This is where Dennehy and Stretch took the notorious on-the-run photos of each other on the balcony and several of Joanne sitting in an armchair, holding a lethally serrated dagger. They were soon joined by Mark Lloyd. Ironically, the first time Stretch and Dennehy saw their ‘happy snaps’ was after the police developed the film.

Lloyd proved to be yet another sucker who fell for Joanne’s charms. Making no bones about it, he said that he became enamoured with Dennehy from the outset. He later gave evidence in court, saying: ‘She ran her hand down the back of my neck. It was like being touched by a rattlesnake. If she had told me to put my head through the car windscreen, I would have done it.’ But was he, just like Leslie Layton and Robert Moore before him, a little out of his depth? Mr Justice Spencer was inclined to believe so:

‘I am quite sure that Mr Lloyd was not a willing passenger in the Vauxhall Astra when it set off for Hereford,’ the judge said in his sentencing remarks. ‘He gave evidence at the trial over a long period and, like the jury, I had good opportunity to assess him. I am also sure that before you [Dennehy and Stretch] left the flat at Kington there was an incident in the kitchen, out of sight of Dennehy, when Gary Stretch showed Mark Lloyd a handgun, which was in the waistband of Stretch’s trousers. Whether it was in fact loaded, as Mark Lloyd believed on the basis of his experience of such weapons, matters not.’

Quite what experience of guns the judge is referring to is a bit of a puzzle, so I asked DS Mark Jinks for the answer. He replied, probably tongue-in-cheek: ‘Lloyd worked in an abattoir but that is probably the closest he got aside from an air rifle.’

Thereafter, Dennehy and Mark Lloyd, with Stretch driving the Vauxhall Astra and their crony, Wilmott, following in a Renault, made their way towards the Oval area of the City of Hereford.

By now DCI Martin Brunning’s Major Crime Unit had connected Dennehy and Stretch to the murder of Kevin Lee and suspected John Chapman might have met a similar fate, so ‘Wanted for Murder’ bulletins were circulated to every police force in the country, especially CID colleagues in Herefordshire, advising them that Stretch could be coming their way. For his part Stretch was easily noticeable because of his enormous height (7ft 3in), with Joanne Dennehy diminutive in comparison at 5ft 8in. They made an odd-looking and easily recognisable couple for he was a mere three inches shorter than the tallest man in the country. {At the time of writing, the tallest man in the UK is English actor and baseball player Neil Fingleton. Born 18 December 1980, Neil stands at 7ft 7.56in and he is listed amongst the tallest men in the world.]

ANPR is a mass surveillance method that uses character recognition on images to read vehicle licence plates. Most have infrared lighting so the system also works at night. Developed in 1976 by the Police Scientific Development Branch, ANPR’s first vital role in a murder case came about with the location and conviction of a criminal gang who shot dead Sharon Beshenivsky, a thirty-eight-year-old Bradford police officer, on Friday, 18 November 2005.

Now, just forty-eight hours after fleeing Peterborough, the police were in hot pursuit and there could be no hiding place: Dennehy must be arrested before she killed again.