Genetics Unzipped is the podcast from the Genetics Society - one of the oldest learned societies dedicated to promoting research, training, teaching and public engagement in all areas of genetics. Find out more and apply to join at genetics.org.uk

Catching a killer

Catching a killer

Licensed from Envato

Licensed from Envato

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Lynda Mann was a summer baby, born in July, who grew into a clever and determined teenager who loved colours and fashion, and she enjoyed sketching outfits.

One November night in 1983, the 15-year-old schoolgirl took a short cut on the way home from her babysitting job, back to her parents’ house in the Leicestershire village of Narborough, but she never arrived. Her body was found the next day on a deserted footpath. She had been brutally beaten, raped and strangled. 

Although police used the best techniques available at the time to create a biological profile of the killer from DNA left at the scene of the crime - namely his blood type, and which versions of certain enzymes he had - it could only narrow down the field of suspects to around 10 per cent of all males.

With no other clues to go on, detectives were stumped and the case remained unsolved. Then came the next one.

Dawn Ashworth was a loving daughter and big sister, who lived in the neighbouring village of Enderby. She was sensible for her 15 years, and always bought her mum a bunch of flowers with the money from her Saturday job. 

One evening late in July 1986, she walked over to visit a friend’s house. Dawn never arrived. Two days later, she was found dead in a local woodland, killed in the same way as Lynda after a considerable fight for her life. 

Again, biological testing showed the same profile as the previous attacker, strongly suggesting it was the same person. But who was he?

At this point a local teenager, 17 year old Richard Buckland came forward and confessed to Dawn’s murder. But he didn’t know anything about Lynda’s death, despite the clear connections between the two. Something didn’t add up. 

Crucially, right in between the two cases, Alec Jeffreys and his team at the University of Leicester had invented the technique that would solve the mystery, taking the 10% chance of getting a match right down to one in a million or more. And when the lead detective on the cases, David Baker, spotted an article about Jeffreys’ genetic fingerprinting in the local paper, he got in touch straight away. 

First of all, Jeffreys’ team compared the DNA sample recovered from Lynda’s body with Buckland’s, and found no match. Next, Baker sent him the sample left at the scene of Dawn’s murder, and again found no match with Buckland, but a perfect match with Lynda’s attacker.

This confirmed that both the cases were linked, that Buckland wasn’t the perpetrator of either of them, and that Leicestershire police had a serial killer on the loose. The news rocked the already frightened tight-knit local communities, who had to face the fact that the murderer probably walked among them. 

The police took a drastic action that seems almost unlikely by today’s standards: asking all the men who had lived or worked in the area in recent years to come forward for DNA profiling. More than 5,000 blood or saliva samples were collected and tested over a period of several months - but none of them matched the genetic fingerprint of the killer. 

This wasn’t entirely unexpected: only a fool would deliberately offer themselves for testing if they were guilty, but the police hoped that their approach would help to flush the killer out. And they were right.

The final breakthrough didn’t happen in a research lab, but in The Clarendon pub just a stone’s throw from the university, where small group of colleagues from a local bakery had gathered on the 1st of August 1987. 

One of them, Ian Kelly, revealed that he’d been asked to stand in and take the police DNA test for another bakery worker, who had given him cash and a faked passport.

The story seemed very suspicious to a woman listening in the group. This evasive colleague was known for his dubious behaviour around women, so she decided to take her concerns to the police.

Her decision was made a lot easier thanks to local fashion magnate, George Davies, the first Chief Executive of the NEXT chain, who put up a hefty reward for information leading to the killer’s capture. The police began to investigate, and soon realised they had their man.

When the suspect was finally arrested on 19th September, genetic fingerprinting told the clear truth: this was the person responsible for the deaths of both girls. However, this DNA evidence wasn’t actually needed in court, as the man plead guilty to his crimes anyway. He was sentenced to life in prison, with a minimum term of 30 years. 

The Enderby case was a dramatic proof of the power of genetic fingerprinting, not only proving the innocence of a key suspect but also closing the net on the true killer, and it captured the nation’s attention. Importantly, it put a highly dangerous man behind bars who, according to those involved in the case, would have almost certainly killed again. 

As well as catching criminals, genetic fingerprinting has also been used to exonerate the innocent. In 1993, the first person on death row in the US was released after being proved innocent by DNA testing. 

Kirk Bloodsworth had been in prison for nine years following his conviction for the rape and murder of nine-year-old Dawn Hamilton in Maryland. Incredibly, genetic testing then revealed that the true killer was a man from the same penitentiary, and the two had even trained together in the prison gym. 

Today, Jeffreys estimates that in excess of 100 million people around the world on some kind of DNA database, although it’s hard to estimate numbers from countries like China. Some countries are even mandating DNA profiling for all their citizens. There are also plenty of people voluntarily putting their DNA data out into the world through direct-to-consumer genetic testing services. 

While this can be a fun way of finding long-lost relatives, it’s also turning into a impressive policing tool. This was proved by the case of the Golden State Killer in 2018, where police managed to catch the perpetrator of a series of rapes and murders by triangulating information from GEDmatch - a free online genetic database where millions of people have uploaded their genetic profile in the hope of linking together branches of their family tree. 

Since then, a number of other crimes have been solved using this kind of information, and a study in 2018 estimated that at least 60% of white Americans could be identified using the genetic information that’s already out there, even if they themselves have never provided their own DNA. That number is only likely to have grown in the past few years, despite growing concerns about personal genetic privacy. 

Finally, this isn’t a true crime podcast, but there are plenty of shows out there that are obsessed with killers and their capture, often through forensic science like DNA fingerprinting. 

While the hunt may be thrilling and the gruesome horror of their crimes chilling - to the point of inadvertently glorifying the perpetrators - we must never forget that the most important people in all these cases are the victims and their families.

At the recent event celebrating 35 years since the publication of Jeffrey’s paper, the President and Vice Chancellor of the University of Leicester, Nishan Canagarajah, announced a permanent PhD scholarship in the names of Dawn Ashworth and Lynda Mann.

It’s a fitting way to honour their memory and their unwilling role in the history of this game-changing technology. Let their names live on, and may they rest in peace.

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